Analysis of Handling Qualities Design Criteria for Active Inceptor Force-Feel Characteristics

Abstract

BackgroundThe force-feel system characteristics of the cyclic inceptors of most helicopters are set based on the characteristics of the mechanical components in the control system (mass, springs, friction dampers, etc.). For these helicopters, the force-feel characteristics typically remain constant over the entire flight envelope, with perhaps a trim release to minimize control forces while maneuvering. With the advent of fly-by-wire control systems and active inceptors in helicopters, the force-feel characteristics are now determined by the closed-loop response of the active inceptor itself as defined by the inertia, force/displacement gradient, damping, breakout force and detent shape configuration parameters in the inceptor control laws. These systems give the flexibility to dynamically prescribe different feel characteristics for different control modes or flight conditions, and the ability to provide tactile cueing to the pilot through the actively controlled side-stick or center-stick cyclic inceptor.

The use of the Open-Loop Onset Point (OLOP) to predict rotorcraft pilot-induced oscillations

“…In this research, OLOP analysis is performed using Hess' structural pilot model. This model has been selected as it has been previously shown to be suitable for rotorcraft closedloop task analysis [20,21]. Furthermore, the model incorporates neuromuscular dynamics, control inceptor dynamics and vestibular feedback.…”

“…As stated in Ref. [21], the form of the proprioceptive feedback is central to the model, and represents the pilots "internal model" of the dynamics. Its form is, therefore, dependent upon the vehicle dynamics, whereby the principles of the crossover model are observed [22];…”

“…The HQSF is evaluated between 1 and 10 rad/s, and is assessed against boundaries determined from previous investigations. The model has been employed in previous studies involving rotorcraft [20,21]. The HQSF provides an assessment of the closed-loop pilot-vehicle model characteristics.…”

The Use of the Open-Loop Onset Point (OLOP) to Predict Rotorcraft Pilot-Induced Oscillations

“…This model has been selected as it has been previously shown to be suitable for rotorcraft closedloop task analysis (Refs. 16,17). Furthermore, the model incorporates neuromuscular dynamics, control inceptor dynamics and vestibular feedback.…”

“…The model has been employed in previous studies involving rotorcraft (Refs. 16,17). The HQSF provides an assessment of the closed-loop pilot-vehicle model characteristics.…”