Measuring the rotational velocity and acceleration based on orbital angular momentum modulation and time–frequency analysis method

Abstract Based on Rotational Doppler Effect of light beam carrying orbital angular momentum, the lateral rotational velocity of the target is able to be measured. However, most of current researches about rotational velocity measurement only focus on the case of constant rotational velocity. Here, a novel method of non-constant rotational velocity measurement is proposed. This method uses the signal processing method of time–frequency analysis, and can simultaneously obtain the rotational velocity and rotational acceleration, without increasing the complexity of the system. A flat disk is fixed to the electric adjustable motor for simulating any non-constant rotational velocity, and a proof-of-concept experiment system is established. Experimental results show that the relative accuracy of rotational velocity is better than 0.7% and the relative accuracy of rotational acceleration is better than 1%. This is of great significance to the field of complex rotating target measurement.