The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
This paper details the design and performance assessment of a unique collision avoidance decision and control strategy for autonomous vision-based See and Avoid systems. The general approach revolves around re-positioning a collision object in the image using image-based visual servoing, without estimating range or time to collision. The decision strategy thus involves determining where to move the...
In this paper, a leader-follower formation control of multiple unmanned aerial vehicles (UAVs) design methodology is proposed to keep the desired formation, while simultaneously deal with the potential collision and actuator faults. The proposed formation control is divided into outer-loop and inner-loop controllers. First, a leader-follower control structure is constructed as the outer-loop controller...
This paper presents a trajectory tracking controller for multi-rotor UAVs to improve their flight performance in the presence of various uncertainties. The proposed tracking system consists of a velocity guidance law based on relative distance and an L1 adaptive augmentation loop for tracking velocity commands. In the proposed structure, the desired velocity generated by the guidance law is the reference...
Cooperative and non-cooperative Sense-and-Avoid (SAA) capabilities are key enablers for Unmanned Aircraft Vehicle (UAV) to safely and routinely access all classes of airspace. In this paper state-of-the-art cooperative and non-cooperative SAA sensor/system technologies for small-to-medium size UAV are identified and the associated multi-sensor data fusion techniques are introduced. A reference SAA...
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...
Motion control of UAVs is an interesting problem due to the nonlinear and underactuacted nature of their dynamics. This paper focuses on position and yaw control of a rotary-wing UAV with state and input constraints using an inner-outer loop control structure. The outer loop generates saturated thrust and reference roll and pitch angles, while the inner loop is designed to follow the reference angles...
This paper describes the development of a Sense and Avoid (S&A) algorithm that can ensure an Unmanned Aerial Vehicle (UAV) being able to avoid collisions autonomously. Firstly, the Closest Point of Approach (CPA) can predict the conflict. Secondly, the developed path planner generates the feasible path using differential geometric guidance and flatness techniques, where the constraints of UAV...
This paper describes the design of model predictive control (MPC) for an unmanned aerial vehicle (UAV) used to track objects of interest identified by a real-time camera vision (CV) module in a search and track (SAT) autonomous system. A fully functional UAV payload is introduced, which includes an infra-red (IR) camera installed in a two-axis gimbal system. Hardware-in-loop (HIL) simulations are...
Optimizing energy consumption of Micro Aerial Vehicles is one of several problems that remains to be solved in the domain of UAVs. In a recent work, a novel quadrotor was introduced that was able, when possible, to roll on the ground thanks to a tilting propeller and caster wheels. In the following work, we build upon this idea with a trirotor helicopter where all the rotors are independently tilting...
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 article proposes a methodology for enabling Unmanned Aircraft Systems (UASs) to avoid obstacles. The strategy, which makes use of a Robust Exact Differentiation (RED), relies on spiral trajectory tracking maneuvers, and is based on a backstepping controller with disturbance compensation. The RED strategy has been adopted since it enables the exact estimation of disturbances from the first moment,...
This paper proposes a control algorithm to solve multiple quadrotor formation problem in a leader-follower configuration. A combination of sliding mode control (SMC) and linear quadratic regulator (LQR) are used for trajectory tracking control of a single robot. Position control, which acts as the outer loop is controlled by LQR for providing the reference attitude angles for the inner loop. SMC used...
In this paper, formation of a group of multiple cooperative unmanned aerial vehicles (UAVs) in a desired geometrical pattern while tracking an aerial target is implemented using decentralized Learning Based Model Predictive Control (LBMPC). The LBMPC is a new control technique that combines statistical learning along with control engineering providing guarantees on safety, robustness and convergence...
This work presents the design of an open-source control architecture specifically tailored to the rapid development and testing of control and coordination algorithms on micro quadrotors. The proposed design extends an existing open-source and open-hardware quadrotor project, i.e., the Crazyflie nano quadrotor, by adding the guidance, navigation and control layers required to accomplish autonomous...
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...
In this article, we proposed a framework to realize vision based multi-UAV cooperative mapping and control with image based visual servoing (IBVS). Equipped with a camera on each UAV platform respecitively, the multi-UAV system with overlapping camera field of view (FOV) can achieve ground mapping and formation cooperatively by image information interaction. Initially, we introduce the Multi-UAV system...
We demonstrate trajectory control of the tip of an inverted pendulum atop a small unmanned aerial vehicle. In this paper we discuss how exploiting the differential flatness of combined systems provides a realization of adequate control. A differential flatness controller is derived for trajectory control of a pendulum tip. Simulation results are presented for tip trajectory tracking with and without...
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...
This paper presents a real-time path planning algorithm for UAVs to avoid collision with other aircraft. Reachable sets are used to represent the collection of possible trajectories of obstacle aircraft. It is used in collision prediction for UAVs in path planning. Once a collision is detected, a sampling-based method is used to generate a collision avoidance path. A second collision check is performed...
This paper considers the control of a multirotor-type unmanned aerial vehicle (UAV) with a suspended load. The load is modeled as a pendulum, with a rigid link. We consider the case when the suspended load is connected to the centre of gravity of the UAV, and the interconnected system is modeled by Kane's method. A nonlinear controller based on the backstepping technique is derived, that ensures trajectory...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.