Application of a Probabilistic Design Environment to the Mission Requirements and Technologies for a Heavy Lift Helicopter

This research presents applications of a probabilistic design environment for the propagation of design uncertainty to the system level to assist in making more educated decisions in the early stages of design. Previous research established the Mission Space Model and the Unified Tradeoff Environment as appropriate probabilistic environments which capture the impact of mission requirements, vehicle attributes and technologies while being amenable to probabilistic techniques. Two probabilistic techniques are introduced and used in conjunction with these environments to show their utility. The first technique is called the Joint Probabilistic Decision Making technique which allows one to assess the probability of meeting multiple objectives simultaneously when the objective data is in the form of a probability distribution (as is the case when design uncertainty is propagated to the system level objectives). Another application introduces a method for conducting optimizations while taking design uncertainty into account. This technique provides coordination between an optimization procedure and a simulation model allowing propagation of design uncertainty. The design environments and probabilistic techniques proposed in this research are demonstrated for a heavy lift helicopter variant of the Future Transport Rotorcraft.