scholarly journals Novel L1 Adaptive Control Approach to Autonomous Aerial Refueling with Guaranteed Transient Performance

Author(s):  
Jiang Wang ◽  
Chengyu Cao ◽  
N. Hovakimyan ◽  
E. Lavretsky
2008 ◽  
Vol 31 (1) ◽  
pp. 182-193 ◽  
Author(s):  
Jiang Wang ◽  
Vijay V. Patel ◽  
Chengyu Cao ◽  
Naira Hovakimyan ◽  
Eugene Lavretsky

2019 ◽  
Vol 142 (3) ◽  
Author(s):  
Prasanth Kotaru ◽  
Ryan Edmonson ◽  
Koushil Sreenath

Abstract In this paper, we study the quadrotor unmanned aerial vehicle (UAV) attitude control on special orthogonal group (SO(3)) in the presence of unknown disturbances and model uncertainties. L1 adaptive control for UAVs using Euler angles/quaternions is shown to exhibit robustness and precise attitude tracking in the presence of disturbances and uncertainties. However, it is well known that dynamical models and controllers that use Euler angle representations are prone to singularities and typically have smaller regions of attraction while quaternion representations are subject to the unwinding phenomenon. To avoid such complexities, we present a geometric L1 adaptation control law to estimate the uncertainties. A model reference adaptive control approach is implemented, with the attitude errors between the quadrotor model and the reference model defined on the manifold. Control laws for the quadrotor and reference models are developed directly on SO(3) to track the desired trajectory while rejecting the uncertainties. Control Lyapunov function-based analysis is used to show the exponential input-to-state stability of the attitude errors. The proposed L1 adaptive controller is validated using numerical simulations. Preliminary experimental results are shown comparing a geometric proportional-derivative controller to the geometric L1 adaptive controller. Experimental validation of the proposed controller is carried out on an Autel X-star quadrotor.


Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3222
Author(s):  
Duc Nguyen Huu

Increasing offshore wind farms are rapidly installed and planned. However, this will pose a bottle neck challenge for long-distance transmission as well as inherent variation of their generating power outputs to the existing AC grid. VSC-HVDC links could be an effective and flexible method for this issue. With the growing use of voltage source converter high-voltage direct current (VSC-HVDC) technology, the hybrid VSC-HVDC and AC system will be a next-generation transmission network. This paper analyzes the contribution of the multi VSC-HVDC system on the AC voltage stability of the hybrid system. A key contribution of this research is proposing a novel adaptive control approach of the VSC-HVDC as a so-called dynamic reactive power booster to enhance the voltage stability of the AC system. The core idea is that the novel control system is automatically providing a reactive current based on dynamic frequency of the AC system to maximal AC voltage support. Based on the analysis, an adaptive control method applied to the multi VSC-HVDC system is proposed to realize maximum capacity of VSC for reactive power according to the change of the system frequency during severe faults of the AC grid. A representative hybrid AC-DC network based on Germany is developed. Detailed modeling of the hybrid AC-DC network and its proposed control is derived in PSCAD software. PSCAD simulation results and analysis verify the effective performance of this novel adaptive control of VSC-HVDC for voltage support. Thanks to this control scheme, the hybrid AC-DC network can avoid circumstances that lead to voltage instability.


2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Maode Yan ◽  
Ye Tang ◽  
Panpan Yang ◽  
Lei Zuo

We investigate the vehicle platoon problems, where the actuator saturation and absent velocity measurement are taken into consideration. Firstly, a novel algorithm, where a smooth function is introduced to deal with the sharp corner of the input signals, is proposed for a group of vehicles with actuator saturation by using the consensus theory. Secondly, by applying an auxiliary system for the followers to estimate the velocities, a control strategy for the vehicle platoon with actuator saturation and absent velocity measurement is designed via the adaptive control approach. Finally, numerical simulations are provided to illustrate the effectiveness of the proposed approaches.


Author(s):  
Giulio Avanzini ◽  
Elisa Capello ◽  
Irene Piacenza ◽  
Fulvia Quagliotti ◽  
Naira Hovakimyan ◽  
...  

2021 ◽  
Author(s):  
Yue Wang ◽  
Zhengguo Zheng ◽  
Ning Sun ◽  
Tong Yang ◽  
He Chen ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document