An Investigation of the Feasibility of Using Video-Based Motion Measurement for Recovering Helicopter Blade Kinematics

Traditionally, kinematic measurements have been made using electro-mechanical transducers which produce a signal which is proportional to the parameter being measured. This approach is unlikely to be replaced by optical tracking techniques, but there are many instances where it is impractical (or even impossible) to attach a mechanical device to the subject. The blades of a helicopter rotot are an excellent case-in-point. While a better understanding of blade kinematics is fundamental to the design of the aircraft, it is difficult to recover three-dimensional kinematics by traditional means under operational conditions. 4D Video believes that an image-based motion measurement system can be used to quantify the rigid-body dynamics of helicopter rotor blades under operational conditions. We propose to investigate the most appropriate means for achieving this objective. Our purpose is to develop a specification which will form the foundation of an SBIR Phase II proposal to develop new hardware and software to perform the required tasks. For the purpose of the present proposal, our effort will focus on two issues: sample-rate, and the development of a customized (circular) tracking algorithm which will take maximum advantage of the predominant motions of the rotor blades. However, other issues have been identified and will be addressed.