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Small unmanned aircraft are being used in an increasing number of applications requiring cooperation between multiple heterogeneous vehicles. Multi-agent control algorithms can be implemented to control such systems but often require an underlying communications framework with integrated payloads. This paper presents a modular heterogeneous multi-agent control framework with payload integration. This...
This paper presents a novel approach to estimate the relative position of an aerial vehicle that is connected to a fixed location on the ground through a taut tether of varying length. The onboard commercial-of-the-shelf (COTS) inertial sensors are the only source of sensory data used for the proposed approach. A three-dimensional (3D) dynamics model of the tethered quadcopter system is presented...
Inspection of industrial chimneys and smoke pipes induces high costs due to production downtimes and imposes risks to the health of human workers due to high temperatures and toxic gases. We aim at speeding up and automating this process with sensors mounted on multicopters. To acquire high quality sensor data, flying close to the walls of the chimney is inevitable, imposing high demands on good localization...
With the advance in technologies and applications involving unmanned aerial systems cooperation among the autonomous agents within such an unmanned system as well as preparedness for responding to adversarial threat to such a system has become of pivotal importance. A multiphase operational scenario of such cooperative and adversarial engagement, motivated by manned aerial engagement scenarios, is...
Small unmanned aircraft systems (UAS) typically do not offer the redundancy typical in commercial aviation due to budget and weight limitations. UAS, therefore, have a nontrivial probability of encountering a scenario in-flight that requires an emergency landing. For fixed-wing UAS, one of the most common in-flight emergencies is a total loss of engine or motor thrust, necessitating that the UAS glide...
This paper proposes a new path following methodology combining with a obstacle avoidance scheme for unmanned quadrotor helicopter (UQH) capable of working in the cluttered and hazardous environments. A new cross-track error prediction based mechanism, where the cross-track error is estimated by utilizing the extend Kalman filter (EKF), is first developed for the path following scheme. Then, the UQH...
We develop a theoretical power consumption model for multi-rotor Unmanned Aircraft Systems (UAS), estimate the model parameters, and validate it by flying an IRIS+ quadrotor UAS and measuring its energy consumption experimentally. The model is derived from the helicopter literature. Such models are required to create UAS flight planning systems.
The development of deliberative capabilities is required to achieve an intelligent fully autonomous behavior of unmanned aerial systems. An important deliberative capability is the generation of collision-free paths in complex environments. This paper presents a robust real-time collision-free path planner used for the horizontal 2D navigation of multirotor aerial robots in dynamic environments. Its...
In this paper we present the use of linear programming to systematically create control software for choreographed UAVs. This application requires the control of multiple UAVs where each UAV follows a predefined trajectory while simultaneously maintaining safety properties, such as keeping a safe distance between each other and geofencing. Modeling and incorporating safety requirements into the movement...
Existence of modeling errors, external disturbances, and inaccurate design assumptions make robustness a desired property for any control system in real-life applications. Linear robust controllers are widely seen as acceptable solutions when systems are controlled close to known equilibrium points and a known trajectory. Unfortunately, linear robust control designs become partially ineffective when...
This article deals with the design of a novel algorithm that combines a Modified Super-Twisting Controller with a High Order Sliding Mode Observer to enable an aerial vehicle to track a trajectory under the assumption that i) its translational velocities are unavailable and ii) there are unmodeled dynamics and external disturbances. We present a mathematical justification that ensures the existence...
This paper presents a mixed-structure control system for a novel ducted fan aircraft in the presence of input constraint, system uncertainty and external disturbance. The control system includes mainly two parts: a robust nominal controller and a L1 adaptive augmentation. The robust nominal controller architecture consists of two loops. The inner-loop is designed as a static state feedback control...
This article addresses the problem of quadrotors following a path geometry under the action of a constant external disturbance and with partial state measurement. To solve these issues, under the assumption of time scale separation between the translational dynamics and the closed-loop rotational dynamics, we propose an integral output robust maneuvering controller in combination with a translational...
A miniature in-situ CH4 concentration measurement instrument based upon tunable laser spectroscopy (TLS) was developed and applied in numerous field campaigns. The instrument, a 3.4 μm laser spectrometer developed at NASA Jet Propulsion Lab (JPL), is lightweight (250g), low power (< 8 W), and high sensitivity (10 ppb s−1). The payload was further developed and integrated onto a small UAV at UC...
Simulation plays an essential role in the development of complex systems. This paper reports on the development of a simulation infrastructure for a fleet of UAVs conceived to probe clouds, using an adaptive sampling scheme that calls for cloud mapping and trajectory planning. The mission is presented, the global approach to solve it and the ensemble of required processes are sketched. An overall...
This paper describes a problem in which a network consisting of a sensor-equipped UAV and multiple beacons, operating in a large geographical space, uses distance measurements to estimate the position of a target and pursue it. The positions of the beacon are also not known to the UAV and needs to be estimated by the UAV, again using distance measurements. Distance measurements are assumed to have...
In this paper, we explore the UAV loss detection and auto-replacement scheme in a multi UAV system. The developed scheme is based on the concept of cooperative multi UAV control, where the cooperation is achieved by broadcasting heartbeats (HBs) and information fusion technology. We first propose the UAV loss detection method by checking the HB time. Subsequently, we present the UAV auto-replacement...
This paper proposes an adaptive robust tracking control strategy for a quadrotor helicopter with parametric uncertainties and external disturbances based on sliding mode control. The inner loop of the control strategy is concerned about the attitude and altitude control of the quadrotor helicopter, while the outer loop is employed to track the desired horizontal positions. By assuming knowledge of...
Micro aerial vehicles, such as multirotors, are developed for applications like autonomous monitoring, inspection, and surveillance. Most of the current application scenarios assume a stationary environment and thus, trajectory generation rehes on static targets. In this paper, we address time-optimal trajectory generation in dynamic environments, e.g., for landing on a moving platform. We extend...
In the context of Unmanned Aerial Vehicle (UAV) teleoperation, the platform is remotely controlled by a human pilot. In order to provide a better situational awareness to the pilot, haptic feedback can be sent through the controller to indicate the presence of obstacles around the UAV. This feedback makes obstacle avoidance easier for the pilot and complements the visual cues obtained from a camera...
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