An Online Estimation of Rotational Velocity of Flying Ball via Aerodynamics

Abstract We propose a novel estimation method of the rotational velocity of a flying ball as well as its position and translational velocity via aerodynamics model by measuring the ball trajectory using the middle speed cameras for table tennis system. The aerodynamics model is complex nonlinear and the measured data of the ball trajectory has quantization errors because the size of the ball is very small in the field of view of the middle speed cameras. Then, we consider the estimation by minimizing the difference between the trajectories which are measured by the cameras and numerically solved by integrating the aerodynamics model respectively. Since the difference is not analytical function, the minimization is solved by the downhill simplex method, where some modification is introduced for improving the converge speed. The effectiveness of the method is verified by numerical simulations.