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Reference governors enforce pointwise-in-time state and control constraints by temporarily modifying the reference command to a nominal closed-loop system whenever the danger of constraint violation exists. In this paper we propose a reference governor with the added capability of resetting internal closed-loop system states as necessary to avoid constraint violation. With this approach the constrained...
This paper presents a discrete-time inverse optimal control scheme for trajectory tracking of a direct expansion (DX) air conditioning (A/C) system. A recurrent high order neural network (RHONN) is used to identify the plant model, and based on this model, a discrete-time inverse optimal control law is derived. The neural network learning is performed on-line by Kalman filtering. The proposed scheme...
This paper considers modeling and control of a planar kite system with flexible cables used to harvest energy from high-altitude winds. The kite is tethered to flexible cables at its leading and trailing edges. The flexible cables are reeled in and out by ground-based winches. The change in winch inertia and cable stiffness as the cable is reeled in and out is also explicitly modeled. The equations...
A nonlinear observer design is proposed for fuel delivery control of a low temperature combustion (LTC) diesel engine. First, a nonlinear engine model, combining the continuous time gas exchange and the event-based closed cycle processes, is presented for the diesel engine. Secondly, an optimization routine based on the extremum seeking scheme is implemented for online observer calibration on a 10...
This paper presents the key design features, the numerical simulations and the experimental ground/flight test activities performed to verify the functionalities of an obstacle detection and avoidance system suitable for various classes of manned and unmanned aircraft. The Laser Obstacle Avoidance and Monitoring (LOAM) system is proposed as one of the key non-cooperative sensors adopted for avoiding...
This paper presents the algorithms enabling real-time 4-Dimensional Flight Trajectory (4DT) functionalities in Next Generation Mission Management Systems (NG-MMS), which are the core element of future Remotely Piloted Aircraft Systems (RPAS) avionics. In particular, the algorithms are employed for multi-objective optimisation of 4DT intents in various operational scenarios spanning from online strategic...
This paper presents an optimal conflict resolution method for multiple unmanned aerial vehicles based on pseudospectral collocation which solves numerically optimal control problems by using non-linear programming. The trajectory of each aerial vehicle is defined by a set of waypoints and the time of arrival at each waypoint. The maneuvers allowed to solve the conflicts are the changes of speed of...
This paper proposes a nonlinear vision based flight control law for the automatic landing of an aircraft. Although a number of methods have been proposed in this domain, our method differs by the following features. First, we do not assume knowledge of the runway size or distance from the aircraft, or the help of a ground technology to guide the aircraft. Second, this design addresses the model nonlinearities,...
This paper describes the theory and implementation of a trajectory optimization layer operating within an energy-aware, airborne, dynamic data-driven application system (EA-DDDAS). The work addresses wind field data estimation, trajectory optimization, and implementation of communication protocols to increase sUAS endurance in persistent sensing missions. The trajectory optimization layer acts as...
This paper describes a navigation algorithm for small fixed-wing airplanes so as to perform path following. The wind gusts need to be taken into account as they play a key role in small prototypes, being the main disturbance when flights are performed. To solve this issue, we use an algorithm known in the literature as carrot-chasing, which includes wind estimates. A Lyapunov stability based control...
The crescent diversity and heterogeneity of vehicles increases the importance of simulation platforms that can reproduce missions using several kinds of vehicles. A platform is being developed at LIACC for this purpose, using Microsoft Flight Simulator X as the simulation engine. Because this simulator has some constraints involving its active simulation area around the player's central aircraft,...
This paper presents implementation of a novel guidance logic for multi-agent fixed-wing unmanned aerial systems using a moving mesh method. The moving mesh method is originally designed for use in the adaptive numerical solution of partial differential equations where a high proportion of mesh points are placed in the regions of large solution variation and few points in the rest of the domain. In...
In recent years, special interest has been paid to the solution of sector design problem. The airspace is partitioned into sectors, each of them being controlled by a group of controllers. Airspace sectors should be designed cautiously, ensuring that no sector would be overloaded during the day. The objective of an airspace design process is to adapt the airspace according to the evolution of the...
A recent air defense missile system is required to have a capability to intercept a tactical ballistic missile(TBMs) by performing engagement control efficiently. The missile defense system has to predict TBM trajectory accurately with cueing information received from an early warning system in order to designate search direction and volume to detect/track TBM as fast as it can and also generates...
It is proposed a navigation system based on the unmanned aerial vehicle (UAV) onboard camera that can land on a moving naval platform. It is considered that, besides the usual sensors, the aircraft is equipped with a RGB digital camera capable of detecting markers located on the ship's deck. The proposed method uses a framework based on a Kalman filter (KF) and an efficient perspective-n-point (EPnP)...
We present the design and implementation of an aircraft collision avoidance algorithm for Unmanned Aerial Vehicles (UAVs). Automatic Dependent Surveillance-Broadcast (ADS-B) is used to detect aircraft. The UAV needs to fly through pre-assigned waypoints while avoiding collisions with other aircraft. The aircraft are indifferent to the UAV. A collision with aircraft are detected by simulating the UAV's...
A controller for a non-deterministic hybrid plant must ensure that the closed-loop system meets some requirement, regardless of what the plant does. When the plant is viewed as an adversary, controller synthesis becomes the task of solving a two-person game to find the system configurations from which the controller wins. For hybrid systems, the moves of each player can be either discrete or continuous...
The requirements, design and simulation of a control system for a precision tracking task, called a Pitch-rate Control Augmentation System (CAS), for the F-16 fighter aircraft model, is considered. This control system is designed over the entire flight envelope using one of the nonlinear Model Based Predictive Control techniques (MBPC), which is called Non-linear Generalized Predictive Control (NLGPC)...
in almost all cities in the world, people breathe dirty air. Air pollution concentration has been rapidly increasing in the major urban areas mainly due to the increasing use of vehicles. Urbanization is changing the people's life style, along with it they have serious issues related to health and environment damage. Hysplit4 is simulation software which is used to simulate the trajectory and concentration...
The presence of optical turbulence in video acquired by cameras viewing scenes at long distances can contribute significantly to degradation. This problem arises routinely, for example, in astronomy where objects of interest reside beyond the earth's atmosphere. Optical turbulence introduces time-varying perturbations in the images as well as blurring. In this paper, we introduce a method for suppressing...
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