Simulation and Experiment on a Novel Integrated Measurement System of Pitch Angle, Phase Angle, and Speed of Turboprop Engine

This paper presents a novel integrated measurement system of pitch angle(
$\beta $
), phase angle(
$\alpha $
)and speed(
${N}_{P}$
) based on phonic wheel to solve the problem of limited installation space of multiple sensors for multiple propellers’ synchrophasing noise reduction control in a turboprop aircraft. Using a set of symmetrical helical marker teeth to reflect the change of the pitch angle and as a phase angle reference point
$\alpha _{0}$
, the phonic wheel with novel structure can realize the simultaneous measurement of three parameters. The axial movement of the phonic wheel reflects the pitch angle, and the spacing between the two marker teeth varies with the axial movement. After signal conditioning and rising edge capture, a series of rising edge instants(they are correspond to the arrival time of the teeth) are extracted by microprocessor, and the marker teeth have shorter time intervals than regular teeth. Hence, pitch angle, phase angle and speed can be automatically obtained through microprocessor’s measurement algorithm. Numerical simulation of COMSOL is employed for optimizing the phonic wheel structure. An experimental platform is designed to test the performance of the integrated measurement system. Results demonstrate that the pitch angle error varies linearly with axial displacement due to the influence of marker teeth, and after linear compensation of
$\beta $
using the interpolation table, the measurement precision of
$\beta $
,
$\alpha $
and
${N}_{P}$
can meet the control requirements of turboprop engine.