scholarly journals Aerodynamic analysis and control for a novel coaxial ducted fan aerial robot in ground effect

2020 ◽  
Vol 17 (4) ◽  
pp. 172988142095302
Author(s):  
Tianfu Ai ◽  
Bin Xu ◽  
Changle Xiang ◽  
Wei Fan ◽  
Yibo Zhang
Keyword(s):  
Disturbance Observer ◽  
Ground Effect ◽  
System Stability ◽  
Bench Test ◽  
Nonlinear Disturbance Observer ◽  
Modeling And Control ◽  
Ducted Fan ◽  
Aerial Robot ◽  
Nonlinear Disturbance ◽  
And Control

Modeling and control for a novel coaxial ducted fan aerial robot in-ground-effect is presented in this article. Based on experiments using the ducted fan bench test, the fitting curve of the ground effect thrust of the ducted fan aerial robot at different heights is obtained. In addition, the flow field simulation results of the prototype with ground effect at different heights can be obtained using computational fluid dynamics software. A simplified model of the prototype for control can be designed based on several reasonable hypotheses that are established using blade element and momentum theory. To compensate for the disturbance associated with ground effect, a nonlinear disturbance observer is designed to estimate the disturbance, and control structure of the closed-loop system is composed of a nonlinear disturbance observer combined with a double-loop proportion–integration–differentiation controller. The results of several numerical simulations and experiments demonstrate the effectiveness of this controller structure. The performances of tracking trajectory and system stability are improved significantly, compared to the situation that the ground effect is not compensated for.

scholarly journals In-Ground-Effect Modeling and Nonlinear-Disturbance Observer for Multirotor Unmanned Aerial Vehicle Control

2019 ◽  
Vol 141 (7) ◽  
Author(s):  
Xiang He ◽  
Gordon Kou ◽  
Marc Calaf ◽  
Kam K. Leang
Keyword(s):  
Flight Control ◽  
Disturbance Observer ◽  
Tracking Error ◽  
Ground Effect ◽  
Exponential Model ◽  
Flight Behavior ◽  
Nonlinear Disturbance Observer ◽  
Loop Control ◽  
Modeling And Control ◽  
Nonlinear Disturbance

This paper focuses on modeling and control of in-ground-effect (IGE) on multirotor unmanned aerial vehicles (UAVs). As the vehicle flies and hovers over, around, or underneath obstacles, such as the ground, ceiling, and other features, the IGE induces a change in thrust that drastically affects flight behavior. This effect on each rotor can be vastly different as the vehicle's attitude varies, and this phenomenon limits the ability for precision flight control, navigation, and landing in tight and confined spaces. An exponential model describing this effect is proposed, analyzed, and validated through experiments. The model accurately predicts the quasi-steady IGE for an experimental quadcopter UAV. To compensate for the IGE, a model-based feed-forward controller and a nonlinear-disturbance observer (NDO) are designed for closed-loop control. Both controllers are validated through physical experiments, where results show approximately 23% reduction in the tracking error using the NDO compared to the case when IGE is not compensated for.

Adaptive nonlinear disturbance observer-based control for stochastic systems with multiple heterogeneous disturbances

2020 ◽  
Vol 42 (11) ◽  
pp. 2020-2030
Author(s):  
Xinqing Li ◽  
Xinjiang Wei ◽  
Huifeng Zhang ◽  
Jian Han ◽  
Xin Hu ◽  
...  
Keyword(s):  
Disturbance Observer ◽  
Composite System ◽  
Stochastic Systems ◽  
Nonlinear Function ◽  
Control Input ◽  
System State ◽  
Nonlinear Disturbance Observer ◽  
Nonlinear Disturbance ◽  
Nonlinear Signal ◽  
And Control

The problem of anti-disturbance control is studied for a class of stochastic systems with multiple heterogeneous disturbances, which include three kinds of disturbance. One is the non-harmonic disturbance coupled with system state and control input. The other one is an unexpected nonlinear signal described as a nonlinear function. The third one is white noise. An adaptive nonlinear disturbance observer (ANDO) is constructed to estimate non-harmonic disturbance. Based on which, a new adaptive nonlinear disturbance observer-based control (ANDOBC) strategy is developed such that the composite system is asymptotically bounded in mean square. Simulation results are given to show its effectiveness of the proposed method.

Modeling and Adaptive Nonlinear Disturbance Observer for Closed-Loop Control of In-Ground-Effects on Multi-Rotor UAVs

2017 ◽  
Author(s):  
Xiang He ◽  
Marc Calaf ◽  
Kam K. Leang
Keyword(s):  
Flight Control ◽  
Disturbance Observer ◽  
Closed Loop ◽  
Ground Effect ◽  
Flight Behavior ◽  
Nonlinear Disturbance Observer ◽  
Loop Control ◽  
Confined Spaces ◽  
Nonlinear Disturbance ◽  
Ground Effects

This paper focuses on modeling and nonlinear control of in-ground-effect (IGE) on multi-rotor aerial vehicles such as quadrotor helicopters (quadcopters). As the vehicle flies and hovers near obstacles such as the ground, walls, and other features, the IGE which is a function of the distance between the rotor and the obstacle induces a thrust that drastically affects flight behavior. This effect on each rotor can be vastly different as the vehicle’s attitude varies. Furthermore, IGE limits the ability for precision flight control, navigation, and landing in tight and confined spaces. A nonlinear model is proposed to predict the IGE for each rotor. To compensate for the IGE, an adaptive nonlinear disturbance observer (ANDO) is designed to enhance closed-loop PID control. The observer and controller are implemented in a simulation framework, where results show significant improvement in performance compared to the case without observing and compensating for the IGE. In particular, it is shown that the ANDO PID closed-loop controller improves the settling time by approximately 60%.

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