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This paper presents a novel obstacle avoidance scheme for UAVs. This scheme is based on the use of a technique recently developed by one of the authors, which is based on a transformation of a variable constraint into an input saturation. In the case of obstacle avoidance, this saturation is designed so as to ensure a safe trajectory around the obstacles, offering a proof of this desired behavior...
This work studies a longitudinal high incidence flight envelope dynamic model for use in a convertible tilt-body vehicle designed for indoor/outdoor environments. The model assumptions are chosen so that a singularity-free nonlinear differential equation system is obtained. The model is complex enough to predict wind tunnel experiments yet simple enough to be described by analytical expressions (instead...
Flight time of micro-UAVs is limited by the battery size they can carry. Typically, they need to land and recharged after about 10 minutes. This paper presents a method for wirelessly charging the UAV battery when it lands, without the need to remove it and replace it. The system consists of a light-weight flexible rectenna array mounted on the UAV body and micro-controller driven power management...
Vector control has been widely used in control of permanent magnet synchronous motors (PMSM). This technique requires an accurate knowledge of the rotor position. In many applications, such as mini-UAV, it is not possible to install any mechanical sensor. Therefore, a sensorless technique using position observer has to be implemented in order to estimate the rotor position. In this paper, we propose...
This paper presents an indirect adaptive control methodology for quadorotors. The methodology aims at controlling a family of quadrotor micro air vehicle with a common set of sensors and processing hardware but with various sizes, configurations, payloads and propeller types. The parameter estimation is based on the Recursive Least Square algorithm which feeds the estimates to a linear parameter varying...
This paper presents an image-based velocity control method for a VTOL UAV. For increased autonomy, a realtime embedded global motion estimation process using efficient feature tracking was developed. The VTOL vehicle is assumed to be equipped with a minimum sensor suite — i.e. a camera, altitude sensor and IMU — and to hover over a featured flat plane. This paper first presents a fast feature-based...
When the extended Kalman filter (EKF) is applied in the aircraft attitude estimation, two defects exist: one is computational complexity; the other is large linearization error. Aiming at these problems, central difference Kalman filter (CDKF) based on Stirling interpolation formulation is applied to the low-cost aircraft attitude estimation system which is of less accurate and high noisy sensors...
The work presented in this paper concerns the active control of flight control devices (sleeves, yokes, side-sticks, rudder pedals, ...). The objective is to replace conventional technologies by active technology to save weight and to feedback kinesthetic sensations to the pilot. Some architectures are proposed to control the device mechanical impedance felt by pilot and to couple pilot and co-pilot...
In this paper a direct predictive current control is proposed for a three-phase flying capacitor multilevel inverter. This control method has been applied to increase the bandwidth of the inverter, defined as the ratio between the switching frequency and the current injected frequency. The current control is applied without modulation, using pre-calculated sequence tables with pre-defined profiles...
A direct predictive control strategy is proposed for a three-phase four-level flying-capacitor (FC) inverter in this paper. The balancing of the FC voltages, a challenge in applications with small capacitors and low switching frequencies, is done without any modulation, simply using tables calculated offline. These allow the realization of fast-dynamics output currents with reduced dv/dt in the output...
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