A new assessment method of the pilot stress using ECG signals during complex special flight operation

With the continuous improvement in the man-machine-designed fighter aircraft, the pilot training intensity has increased. Complex special operation of the fighter aircraft is greatly affected by flight conditions and human control reliability, which imposes a great burden on the pilot psychophysiologically. To understand the intensity of the stress on the pilot, which is a crucial parameter, accurate evaluation of the changes in the stress intensity of the pilot during the flight is very important. This study aimed to analyze the stress intensity of pilots by collecting electrocardiogram (ECG) signals during the long flight involving 11 pilot trainees. First, an improved soft-threshold denoising method for the ECG data and an improved differential threshold method were used to process the first-order difference and the threshold value to the filtered signal to determine the R wave. Then, the multiscale analysis method was used to fuse the area of the heart rate curve of the pilots. The method of flight training and the division of the stress stage were derived. Further, the functional relationship of the stress intensity with the frequency of training was constructed. All these effectively improved the performance of the flight operation training and helped make a reasonable training plan. This was of great practical significance to the measurement and evaluation of the stress state of the individuals in dangerous jobs, such as special flight operations, high-altitude skydiving, bungee jumping, etc.