| Respiratory activity, being one of the vital signs of life, is essential to monitor as changes in normal breathing pattern can provide hints of irregular body functioning. In the past years, there have been numerous advancements in techniques to monitor respiratory activity. In recent times, IMUs (Inertial Measurement Unit) have been very popular in many domains including tracking of motion, orientation, location, acceleration and trajectories of any object or person wearing them. Although, a single IMU has also been used to detect breathing motion, it tracks all kinds of motion and does not differentiate between breathing and other motions of the body. Consequently, any kind of body motion performed while recording respiration, reflects in breathing motion; Thus, distorting respiratory measurements unless the body is kept still. This problem is addressed and combated in this research by proposing and developing a novel method that uses two IMU sensors to monitor respiratory activity.;This research uses an assembly or a network of two wearable, wireless IMU sensors custom-made by Department of Electrical Engineering at San Diego State University. Each sensor incorporates 9-axis motion processor and wireless (Bluetooth) transmitter. After the sensors are appropriately placed, the body is motioned keeping breathing intact. This research applies principles of robotics, Denavit-Hartenberg convention, Forward and Inverse Kinematics, and mathematical calculations to extract relative motion between the two sensors by using D-H 3-D modelling to decompose motions experienced by the IMUs. The relative angular motion extracted thus, predominantly yields respiratory activity (amidst body motions).;This research proves to be a booming concept that uses an IMU pair to extract and record breathing motion. It can contribute widely to the scientific society. The wearable and wireless sensors are suitable for several applications as they do not restrict body motion or the choice of location for data collection. The proposed technology can find use in medical and sports industry. Its improvised real-time version can specially be useful for elderly people and patients suffering from Asthma to monitor their breathing and diagnose abnormality during daily-life activities. A refined form of this technique can also help diagnose Central Sleep Apnea. |
