A methodology utilizing spatial kinematics principles with angular rate sensor and accelerometer data to evaluate ATD head and leg flail kinematics in experimental aerospace seat dynamic impact testing
In dynamic aircraft crash testing, the head trajectory of an anthropomorphic test device (ATD) is typically recorded by photometric analysis from the high-speed video. While photometric analysis can provide useful data results, it does have a number of short comings including the need to correct for lens distortion, perspective, parallax, and scale factor. Additionally, photometric analysis can be operator dependent which can result in variability of the output head trajectory. This dissertation describes a method of evaluating the ATD head trajectory from accelerometer and angular rate sensor data by use of an algorithm utilizing Euler parameters and spatial kinematics. Local angular velocity data is utilized in conjunction with Euler parameters and numerically integrated, solved with the Runge-Kutta 4th order method, to generate a transformation matrix at each time step. The local acceleration data is then converted to global acceleration using the transformation matrix data, accounting for gravitation influence and global coordinate system movement through the event. The methodology developed to calculate the ATD head trajectory and leg flail from the local instrumentation data is validated through experimental testing. These tests are conducted at the component level and then, incrementing complexity, with a head component tester and finally with a complete ATD in multiple test cases. The output displacement data is compared to a known trajectory path and 2D and 3D photometric analysis data. Overall, this dissertation combines the use of classical mechanics and experimental test procedures in a unique, viable, and efficient method to evaluate ATD head and leg flail kinematics.
Thesis (Ph.D.)-- Wichita State University, College of Engineering, Dept. of Mechanical Engineering