Fast calculation method for helicopter reachable domain in forward flight

Helicopter reachable domain can be used to generate airspace security situation and improve the helicopter safety level in a low-altitude complex environment. In order to meet the demand on real-time performance and accuracy, a fast calculation method was proposed. The helicopter control zone was computed through energy method and the helicopter reachable domain mathematical model was established by combining kinematical equation with control zone. Based on optimal control theory, the boundary points of reachable domain were solved. The problem of constructing reachable domain in real time was transformed into the problem of calculating the boundary points. Two-dimensional and three-dimensional examples of AH-1G helicopter were analyzed and the results of the proposed algorithm were compared with differential inclusion method. The numerical results show that the control zone is time varying and should be computed on the basis of real-time flight status. Helicopter reachable domain in forward flight can be calculated in real time using the proposed algorithm and has high precision.