Self-sufficient sensors based on energy harvesting validation and evaluation study of tram bearing diagnostics using simulation techniques

Abstract

Wireless sensors enable fast and easy recording of measurement data -also known as plug and play. Currently a very big challenge is providing of a stable long range power supply. The use of energy harvesting provides an opportunity to supply wireless sensors and to improve the stability of the sensor networks. To estimate the lifetime of sensors (in a network) a simulation tool based on MATLAB/Simulink was developed. IndexTermsEnergy Harvesting, simulation, MATLAB/Simulink, Energy self-sufficient measurement, vibrations diagnostic I. WIRELESS SENSORS FOR VIBRATION DIAGNOSTIC IN TRAMSThe right time for replacement a bearing of a tram in the "Leipziger Verkehrsbetriebe LVB" (Leipzig Public Transportation Service) can be found out only after costly inspections. This can result in an outage of the rail car lasting over several days.In the research project "TRAINCON" the University of Applied Sciences Leipzig (HTWK Leipzig), in cooperation with other project partners, developed methodology for wear detection using wireless and energy self-sufficient sensors. This methodology is based on several wireless, temporary affixed sensor nodes in a sensor network to measure for material wear. The measured data will be automatically recorded and if necessary preprocessed and finally sent over a base station where the master display is located. In a later stage an analysis of the measurement data will be performed and the system state will be automatically computed by using different types of evaluation methods. That way we will make it possible to infer a suggestion for a maintenance task.The use of energy self-sufficient sensors enables the use of the environmental energy to satisfy as much as possible, their energy requirements. The appropriate number of measurements depends on the type and distance of the data transfer as well as the available quantity of useable and storable environmental energy. A. Sensor Systems in TramsTo enable wear detection over acoustic emissions (structure-borne sound) as characteristics it is necessary to use acceleration sensors with a sample rate of more than 10 kHz. Depending on the sampling time interval, it might result in a high number of measurements to be sent or to be preprocessed before sending (to be compressed). harvester transceiver energy management storage sensor acoustic emission μ-controller wireless sensornode environmental energy Fig. 1 Sensor systems on Trams (picture reference LVB)The sensors' requirements for deployment in a tram are as follows: -be wireless -highly reliable -high energy lifetime -small size B. Energy Self-sufficient MeasurementThe use of energy harvesting, with other word to harvest the unused one as minor product accrued energy, provides 613

Design of a Wireless and Energy Autonomous Sensor Network for Condition Monitoring of Tram Drive Components

“…On the basis of simulation investigations, the energy consumption of the electronic components can be estimated under certain conditions (e.g., duration of measurement pauses, sampling rate, and transmission rate) [1,16,17]. In addition, the selection of the electronic components was optimized with regard to their energy consumption.…”

“…Thus, the intervals between two measurements can be longer until the first condition describing changes in the measurement data starts to appear. During this time, sufficient energy can be harvested via the VEH to be able to send new measurement data [16,17]. In addition, the used microcontroller board (ESP8266 demo kit) is very well suited for this task, since it already has energy-saving strategies due to various operating modes ("active mode", "sleep mode" or "deep sleep mode") [20].…”