Optimal Control Based Flight Control Law Clearance for eVTOL Using Postoptimal Sensitivity Analysis

In this paper, the effectiveness of the optimal control-based method for clearance problem is investigated, which examines the robustness of the control law by searching for the worst conditions. Specifically, the method is applied to a novel-configured electric Vertical Take-Off and Landing (eVTOL) aircraft with uncertain parameters considered. The criterion under research is the normal load factor limit exceedance criterion. By applying the bi-level optimization scheme, worst-case controls and parameters values are determined in two layers of problems to find the highest load factor that is likely to violate the criterion. The post-optimal sensitivity analysis on the cost function is carried out at the optimal point of the nominal problem. This method helps decide the influence of each parameter and reduce the dimension of the parameter space of the upper-level problem by selecting a subset of parameters. The methods mentioned above appear to perform well and can efficiently be applied to the parameter-dependent clearance problem.