Pre­cisi­on Sen­sors for Struc­tu­ral Health Moni­to­ring

New pre­cisi­on sen­sors from the Chem­nitz-based elec­tro­nics com­pa­ny GEMAC sup­port the moni­to­ring of buil­dings and brid­ges. This solu­ti­on approach will be pre­sen­ted for the first time at the SPS/​IPC/​Drives tra­de fair (Hall 7, Stand 297), which will take place from 22 to 24 Novem­ber 2016 in Nur­em­berg.

In coöpe­ra­ti­on with Deut­sche Bahn, the GEMAC – Gesell­schaft für Mikroelec­tro­nik­an­wen­dung Chem­nitz mbH deve­lops pre­cisi­on sen­sors for the moni­to­ring of buil­dings and brid­ges. Up to now, two sen­sors have been deve­lo­ped : on the one hand, a sen­sor for high-pre­cisi­on tilt mea­su­rement in the ran­ge of ±5° and, on the other hand, a sen­sor for pre­ci­se acce­le­ra­ti­on and dis­pla­ce­ment mea­su­rement. The first men­tio­ned sen­sor impres­ses with an accu­ra­cy of up to 0.001° and a reso­lu­ti­on of 0.0001°. The mea­su­ring ran­ge of the sen­sor for acce­le­ra­ti­on and dis­pla­ce­ment mea­su­rement is ±2 g, with a reso­lu­ti­on of 1 µg. As the­se sen­sors com­mu­ni­ca­te via a CAN inter­face, they are easy to wire and enab­le robust and inter­fe­rence-pro­of com­mu­ni­ca­ti­on.

Initi­al field tests with pro­to­ty­pes were suc­cess­ful­ly car­ri­ed out in 2015. The­se sen­sors are then trans­fer­red to series pro­duc­tion. The aim is to deve­lop an out-of-the-box solu­ti­on. Howe­ver, much more data has to be collec­ted on various struc­tures.

The advan­ta­ge of distan­ce mea­su­rements based on acce­le­ra­ti­on data is that no local refe­rence is requi­red. This opens up the pos­si­bi­li­ty of per­ma­nent moni­to­ring, espe­ci­al­ly for brid­ges. Howe­ver, a cali­bra­ti­on of the acce­le­ra­ti­on sen­sors at the instal­la­ti­on loca­ti­on is requi­red for dis­pla­ce­ment mea­su­rement. A limi­ta­ti­on of the distan­ce mea­su­rement by means of acce­le­ra­ti­on is that the dou­ble inte­gra­ti­on of the acce­le­ra­ti­on data for obtai­ning the distan­ce signal has to be car­ri­ed out sub­se­quent­ly for cer­tain time win­dows (e. g. the dura­ti­on of a train crossing) and can­not be car­ri­ed out in real time. Pre­vious approa­ches for the long-term mea­su­rement of a path using acce­le­ra­ti­on data and its dou­ble inte­gra­ti­on are not sui­ta­ble for the app­li­ca­ti­on. By com­bi­ning acce­le­ra­ti­on and pre­cisi­on tilt mea­su­rements, the posi­ti­on of brid­ges can now be moni­to­red over a long peri­od of time wit­hout any pro­blems. This opens up nume­rous new app­li­ca­ti­ons for the incli­na­ti­on and acce­le­ra­ti­on sen­sors of GEMAC in the field of struc­tu­ral health moni­to­ring. In addi­ti­on to dis­pla­ce­ment mea­su­rement, the­se acce­le­ra­ti­on sen­sors also offer the pos­si­bi­li­ty of mea­su­ring natu­ral fre­quen­cy up to 200 Hz.