Identifying pilot model parameters for an initial handling qualities assessment
It is desirable to make an assessment of likely handling qualities to identify any deficiencies in a helicopter control system at an early stage in the design process before an expensive and potentially dangerous prototype is constructed. Inverse simulation offers a modelling technique that can be used for generating the data needed for such an assessment. Inverse simulation differs from conventional forward simulation in that the vehicle flight path is the input and the state and control time histories required for the task are generated. The inverse algorithm however, does not account for the pilot contribution to the flight data, thus the work herein demonstrates a method whereby this can be achieved. To incorporate pilot effect into the Helinv generated data, the latter is applied as the command signal to the Man-Machine Control System (MMCS), which is a closed loop system encompassing the helicopter vehicle dynamics and a model of the pilot known as the Precision Pilot Model (PPM). The PPM Human Equalisation Characteristics (REC) are determined via a constrained optimisation technique and the pilot effect is added in the system output. Validation of this technique is achieved through a case study whereby several operators, with different levels of experience, pilot a reduced order Puma helicopter model through a predefined mission task in a flight simulator constructed during the project. The equalisation characteristics are then determined for each pilot and compared with those generated using Helinv. A handling qualities assessment is presented for both sets of results and conclusions concerning the validity of Helinv with additional pilot effect finally drawn.