Real-Time Helicopter Weight and Mass Center Estimation

Real-time estimates of weight and mass center location for helicopters are desirable for flight control and condition-based maintenance purposes.  While methods to estimate mass parameters of helicopters have been developed, they often assume near-perfect knowledge of helicopter dynamics and have been validated only through simulated measurement data.  Our work aims to experimentally validate a method for weight and mass center estimation using an ALIGN T-REX 600e R/C helicopter.  The estimation algorithm utilizes an extended Kalman filter (EKF) which estimates the helicopter states along with the weight and mass center location in real-time.  Nonlinear system identification is performed using maximum likelihood estimation to create an accurate dynamic model for use in the EKF.  Results show that given a reasonably accurate dynamic model, weight and mass center location can be reliably estimated in non-descending flight conditions.  Weight estimation is shown to be robust to sudden weight changes during flight.  Detailed flight test studies characterize estimation error in weight and three-dimensional mass center position using the EKF formulation.

Plot of Coll vs Weight vs Time Plot of weight shift

References:

  1. B. Taylor, J. Rogers, “Experimental Investigation of Helicopter Weight and Mass Center Estimation,” 2013 AIAA Aerospace Sciences Meeting, Grapevine, TX, January 7-10, 2013.
  2. B. Taylor, J. Rogers, “Experimental Investigation of Real-Time Helicopter Weight Estimation,” Journal of Aircraft, Published Online Ahead of Print, 2014.