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This paper presents a model based robust control scheme for tail-sitter hybrid Unmanned Aerial Vehicles (UAVs) in forward transition phase. To tackle the problem from high nonlinearity and uncertainties in transition dynamics, a comprehensive model form is constructed, and a so-called Robust Perfect Tracking (RPT) control method is utilized in attitude tracking. Experiment results are given to demonstrate...
This paper presents a systematic control synthesis method in order to achieve auto-transition for KH-Lion, a tail-sitter hybrid UAV. Although there are huge potentials in various applications of the hybrid tail-sitter UAVs, the transition between vertical take-off and landing mode and cruise mode is still a challenge now. Due to the complex behaviour that the transition can generate, it is very difficult...
This paper presents a comprehensive modeling approach for tail-sitter hybrid UAVs featured by vertical take-off and landing (VTOL) and cruise flight capabilities. The modeling approach includes all essential components, such as full angle of attack envelope wing and fuselage aerodynamics, sideslip wind effect and actuator dynamics. A unified formulation comprising all model components is derived to...
As a promising candidate applied in direct-drive applications due to high torque characteristics at low speed, vernier permanent-magnet (VPM) machines have been paid increasingly attention in many direct-drive fields, such as electric vehicle propulsion and wind power generation [1–2].
In this paper, we present a novel hybrid UAV, U-Lion, which has autonomous VTOL and cruise flying capabilities. The reconfigurable wings are designed so that the structure of U-Lion is aerodynamically efficient in both flying modes. Vectoring thrust and the multiple control surfaces tail are implemented to increase the controllability for better maneuverability and stronger rejection to wind gust...
Majority of today's fixed-pitch, electric-power quadrotors have short flight endurance (< 1 hour) which greatly limits their applications. This paper presents a design methodology for the construction of a long-endurance quadrotor using variable-pitch rotors and a gasoline-engine. The methodology consists of three aspects. Firstly, the rotor blades and gasoline engine are selected as a pair, so...
The principle of a dual mechanical port (DMP) machines is proposed in 2002 [1], and since then, many different topologies of DMP machines have been proposed [2]. The structure of the DMP machine which has been proposed in [3] is compromised by inner motor and outer motor, the inner motor is compromised by inner rotor and outer rotor, and the outer motor is compromised by outer rotor and the stator,...
Mechanical gearbox, which plays significant roles in vehicular transmission system, inherently suffers from the drawbacks of wear-and-tear and regular maintenance [1]. Magnetic gears are considered as the preferred gearing device for vehicular transmission system because they have the merits of silent operation, maintenance free and physical isolation. However, the gear ratio of magnetic gear is fixed...
In this work, we provide a nonlinear mathematical model identification methodology of an autonomous micro quadrotor, and the design of its orientation and position controllers. In the model identification, we specifically focus on the brushed D.C. motor dynamics, which further breaks down into three different segments: voltage generation, motor dynamics, and force/torque generation. Test bench experiments...
This paper presents the work that has been done to derive an accurate nonlinear model for a miniature fixed-pitch coaxial helicopter. Starting from the Newton-Euler rigid body dynamic equations, forces and torques generated at various parts of the UAV have been identified and formulated. The physical meanings behind the model are clearly explained, and the methods of identifying all the important...
In this work, a novel FES-robot system was developed for wrist rehabilitation training after stroke. The FES-robot system could be continuously controlled by electromyography (EMG) from the residual wrist muscles to facilitate wrist flexion and extension tracking tasks on a horizontal plane by providing assistance from both FES and robot parts. The system performance with five different assistive...
A three-dimensional (3D) transient finite element analysis (FEA) approach taking into account the effects of steel lamination core loss is proposed. When using the T-Ω method, the effects of lamination core loss are considered by introducing an additional field component in lamination regions, which is derived from the instantaneous core loss in the time domain. The proposed approach is validated...
A combined attitude stabilization control method is proposed on the bases of using both flywheel and magnetic torquers in case of flywheel failures. Firstly, a combined control scheme is provided with control allocation loop, and the control allocation and magnetic unload algorithms are further developed. Considering a specified condition when only the pitch axis flywheel is available, a strategy...
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