Angular Velocity Estimation for a Pneumatic Motor with Pressure and Flow Sensors

Carbon fiber reinforced polymer (CFRP) materials are widely used in the aerospace industry. Repair of CFRP materials entails a process referred to as scarf sanding wherein damaged areas are milled and removed. However, this process generates substantial amounts of carbon dust. Therefore, to ensure explosion-proof operation, motors operating without electrical power, such as pneumatic motors, must be utilized for the automation of scarf sanding. Additionally, angular velocitysensorless control of the pneumatic motor is essential. In this paper, we propose an angular velocity estimation method based on the mathematical model of a pneumatic motor. Further, we propose a new method for acquiring the angular velocity of a pneumatic motor based on the fast Fourier transform (FFT) of the measurements from a volume flow rate sensor installed in the motor air supply piping. Finally, we integrate both methods to devise a hybrid angular velocity estimation method. The verification results demonstrate that the hybrid method can accurately estimate the angular velocity in the range of 0–1600 RPM.