Sensor packaging design for continuous underfoot load monitoring.
Continuous force measurement can provide valuable insight to the efficacy of limb loading regimes during fracture rehabilitation. Currently there is no load monitoring device that is capable of more than 1 h of continuous recording. To enable continuous underfoot load monitoring a piezoresistive pressure sensor was encapsulated in a non-compressible silicone gel. This basic approach to signal transduction was implemented in three continuous underfoot load sensor designs. Design I constrained the gel in a rigid urethane housing. Design II constrained the gel in a silicone elastomer bladder. Design III utilized a hybrid approach by constraining the gel with a rigid upperplate inside of an elastomeric bladder. All three designs were subjected to bench and human testing. Design I outperformed the other two designs showing high linearity (correlation coefficient of 1), low static drift (<1%) and low dynamic drift (<3%) and captured the largest percentage of weight during human testing (35%). The sensor was designed, tested and shown to be durable and accurate for a 2 week window of time. This sensor has the low cost and high performance required for large scale clinical tests to correlate limb loading and fracture healing rates.
Department of Biomedical Engineering, University of Utah, 72 S. Central Campus Dr., Rm 2646, Salt Lake City, UT 84112, USA.
Kylee
K
North
Erik N
EN
Kubiak
Robert W
RW
Hitchcock
D001696:Biomechanical Phenomena; D002138:Calibration; D004867:Equipment Design; D005080:Exercise Test; D005528:Foot; D017102:Fracture Healing; D006801:Humans; D009989:Orthotic Devices; D011312:Pressure; D013314:Stress, Mechanical; D016474:Weight-Bearing