An API for inertial sensors prototyped in MATLAB is presented, targeting applications relating to physical therapy and injury prevention. The API provides facilities for easy data calibration, mote orientation calculation using rotation matrices, gravity calculation, and velocity and displacement calculation using the Verlet algorithm. Lateral and angular velocity drift is canceled through a novel approach of mote stability detection and recalculation of absolute mote orientation with the gravity vector obtained from the accelerometer. Frequency detection is performed by the API on any sensor signal using autocorrelation and a linear Kalman filter is also implemented to filter gyroscope readings. The test platform for evaluation was the Shimmer 2R wireless sensing mote collecting accelerometer and gyroscope readings at a rate of 256 Hz. Evaluation was done with drills relating to anterior cruciate ligament (ACL) injury: a jump height measurement test, hop count test, and a drop test with angle measurements on the knee. Results show a mean height measurement error of 3.27±0.5 cm (14.36%), hop counting error of 0.95 hops (1.82%), knee flexion error of 4.11±1 degrees (5.09%), knee inward bend error of 4.12±1 degrees (15.3%) and outward of 6.66±1 degrees (9.06%). Portability of the API to an embedded platform is discussed with reevaluation of the experiments with lower sampling frequencies; a sampling rate as low as 64 Hz still shows good accuracy.
|Commitee:||Baas, Bevan, Wilken, Kent|
|School:||University of California, Davis|
|Department:||Electrical and Computer Engineering|
|School Location:||United States -- California|
|Source:||MAI 50/05M, Masters Abstracts International|
|Subjects:||Computer Engineering, Electrical engineering, Computer science|
|Keywords:||Accelerometer, Acl, Api, Gyroscope, Inertial sensor, Mote|
Copyright in each Dissertation and Thesis is retained by the author. All Rights Reserved
The supplemental file or files you are about to download were provided to ProQuest by the author as part of a
dissertation or thesis. The supplemental files are provided "AS IS" without warranty. ProQuest is not responsible for the
content, format or impact on the supplemental file(s) on our system. in some cases, the file type may be unknown or
may be a .exe file. We recommend caution as you open such files.
Copyright of the original materials contained in the supplemental file is retained by the author and your access to the
supplemental files is subject to the ProQuest Terms and Conditions of use.
Depending on the size of the file(s) you are downloading, the system may take some time to download them. Please be