Yiyuan Zhao's research while affiliated with University of Minnesota Duluth and other places

... The minimum forward flight speed of the TR UAV and the power provided by the rotor determine the tilt conversion corridor of the TR UAV. In the tilt conversion corridor, choosing an optimal tilt path is essential for the TR UAV to complete a safe and stable conversion flight [9]- [14]. ...

... These separation distances can be represented as a volume that surrounds each aircraft, called the Protected Zone (PZ). Hence, a conflict occurs, if there is any interference between these protected zones [14]. For example, in tactical collision alerting systems the PZ is taken as a sphere of 500 ft in diameter, or it can be represented in terms of time instead of distance [11]. ...

... In addition to the standard minima set by this operational requirements, additional buffers are added due to the surveillance uncertainty which lead to a separation minima structure defined in the RESET Model, developed in the late 2000s within the RESET project, it has been validated as a prototyping model for testing specifications for new separations according to A. Groskreutz and Rodriguez [3]. It is a simplified theoretical model based on the studies developed by Reynolds and Hansman [4], the Rockman model[5], and the Ennis and Zhao aircraft protected zones [6]. This model can be used for determining the impact on Separation Minima of new operational concepts or enablers, like those proposed by EARTH project. ...

... Finally, for the process optimization problem, the common practice is to convert the problem to an optimal control problem, as [13][14][15][16][17][18][19][20] did, which is limited to the specific mission backgrounds. Even though the literature on the transition process of V/STOL is comparatively limited, the optimal control method is still valuable, since the optimization methods are flexible for different control strategies, as [21][22][23][24] applies the method to various objects, regardless of the specific controller design, with [25][26][27][28] designing different controllers based on this method. ...

... With the air traffic controllers, aeronautical-specific communication protocols (e.g., ACARS3) are used over a satellite link or a terrestrial link based on VHF/HF3 or 1090 MHz Extended Squitter (1090-ES) [1]. As more and more aircrafts are equipped with GPS and Wi-Fi transmitters, it becomes easier to design systems that will allow aircrafts to interact autonomously with each other (Figure1). ...

... Thus, this displacement is the shortest way out of the intruder's protected zone. Dividing the resolution vector by the time left to CPA yields a new speed, which can be added to the ownship's current speed vector, resulting 5 126 REINFORCEMENT LEARNING TO IMPROVE AIRSPACE STRUCTURING in a new advised speed vector. From the latter, a new advised heading and speed can be retrieved. ...

... For recent research on trajectory optimization related to collision avoidance, see Refs. [4][5][6][7][8][9][10][11]. In spite of the progresses, the possibility of collision still exists due to a variety of factors such as pilot error, aircraft malfunction, air traffic control system breakdown, bad weather, difficult environmental conditions, and so on. ...

... The literature on trajectory prediction and associated challenges in ATM is vast, and the reader is referred to the comprehensive review paper by Mondoloni and Rozen [2]. The theoretical basis for aircraft trajectory prediction and aircraft performance models for ATM has been well established for many years [4], [5]. However, due to the limitations in available data for ATM applications and the inherent coupling between the variables of interest, several variations are possible in the estimation of APM parameters using historical data. ...

... Traditional methods explicitly model aircraft behavior based on kinematic equations of motion. Several studies predicted the nominal trajectory by propagating the state estimates into the future [3], [4] or to the next flight segments [5]. Aircraft performance models, such as Base of Aircraft Data (BADA) [6], were also developed based on aircraft dynamics models for trajectory simulation and prediction. ...

... There are few investigations on the flight performance comparative analysis of different takeoff-tilting schemes and trajectories. An optimal takeoff-tilting scheme and trajectory can not only solve the problem of control redundancy, but also improve the stability of body attitude and help reduce the time and energy consumption [12]. ...