A test evaluation of a Pilot-Induced-Oscillation prediction criterion

This paper presents evaluation procedures, concepts, and results from a limited test to evaluate the ability of the Open-Loop Onset Point (OLOP) criterion to predict Pilot-Induced-Oscillations (PIO) in the presence of rate limiting. The OLOP criterion was developed by DLR. This paper examined the ability of OLOP to predict PIO on incorporating flight control systems with various rate limits imposed on the actuator. Two Pilot Models were examined for use with OLOP: the recommended pure gain model, and the Modified Neal-Smith model. Test pilots performed a handling qualities evaluation on each configuration using two tracking tasks. PIO ratings were compared with OLOP calculations for correlation. The results show positive correlation between OLOP and pilot ratings. The criterion was found to be useful. This paper presents recommendations on how OLOP might be applied as a design tool.