Boundary Avoidance Tracking: A New Pilot Tracking Model

Abstract

Research concerning pilot-in-the-loop handling qualities has traditionally assumed that a pilot is focused upon maintaining a specific parameter, such as aircraft attitude or normal acceleration. This assumption has resulted in many important results and, by modeling this type of pilot behavior, a significant amount of predictive ability. In spite of these successes, many aspects of pilot control remain very difficult to predict. It is hypothesized that pilots often engage in a previously unrecognized type of tracking, boundary-avoidance tracking, where the goal is to avoid a hazardous parameter, such as ground impact, or a routine limit, such as an assigned minimum altitude. A variety of Simulink ® models were built to study this phenomenon and it was found that treating the pilot gain as a function of the time to exceeding a given boundary can result in the type of control inputs typical of pilots in such situations, including the worst types of pilot-induced oscillations. Nomenclature K bm= maximum boundary gain t b = time to boundary t min = minimum time to boundary with no boundary feedback t max = time to boundary when boundary feedback is the maximum boundary gain, K bm τ b = time delay for boundary-avoidance feedback x b = displacement from boundary

Investigations on boundary avoidance tracking and pilot inceptor workload

“…This behaviour is referred to as point tracking. In 2004, Bill Gray introduced a new theory which suggests that there are situations when the pilot abandons the point tracking task in favour of boundary avoidance tracking (BAT) [2,3], a control action based on the avoidance of unfavourable or even dangerous conditions like stall, over-g or ground impact. The concept was mainly based on anecdotal evidence he experienced during his career as a test pilot.…”

“…First, Simulink simulations were performed to investigate the phenomenon. These efforts were intensified and a mathematical BAT model as well as a first application of a corresponding FTT were presented in 2005 [3]. Also, the implications of certain BAT model parameters on tracking performance were investigated.…”

“…Gray first introduced his theory in 2004 [2,3]. The expressions ''Boundary Escape Tracking'', ''Boundary Avoidance Tracking'' and ''Point Tracking'' were introduced and initial considerations were given to a suitable BAT pilot model.…”

Voluntary Pilot Action Through Biodynamics for Helicopter Flight Dynamics Simulation

“…More sophisticated voluntary pilot models can be used, for example when specific tasks need to be addressed (e.g. models derived from Gray's work on Boundary Avoidance Task (BAT) [41][42][43]). The previously discussed simple models are preferred in this context since the focus is on producing the effect of the pilot's intentional behavior throughout the same detailed biomechanical model that is used to simulate the involuntary behavior.…”

Practices to identify and preclude adverse Aircraft-and-Rotorcraft-Pilot Couplings – A design perspective

“…The new "Real-time Phase Aggression Criterion" (PAC) method [21,30,33] is based upon ROVER and the Pilot-Inceptor Workload (PIW) method proposed by Gray [91,92]. PIW was developed to identify A/RPC susceptibility in Boundary Avoidance Tracking (BAT) tasks, i.e.…”