Estimation of human reaction time delay during balancing on balance board

Human balancing on a balance board is modelled as a delayed proportional-derivative control mechanism with unknown feedback delay. The mechanical model implies that there exists a critical delay, for which no control gain parameters can stabilize the system. This theoretical critical delay is determined by numerical analysis for different geometries of the balance board. Then the results are compared to real balancing trials on balance boards with the same geometries. Comparison of the unsuccessful balancing trials to the theoretical critical delay suggests that the feedback delay of human balancing task is between 20ms and 110ms.