Closed-Loop Q-Learning Control of a Small Unmanned Aircraft

2020 ◽  
Author(s):  
Robert J. Clarke ◽  
Liam Fletcher ◽  
Colin Greatwood ◽  
Antony Waldock ◽  
Thomas S. Richardson
Keyword(s):  
Closed Loop ◽  
Learning Control ◽  
Unmanned Aircraft ◽  
Q Learning

scholarly journals Open-closed Iterative Learning Control Algorithm for Exoskeleton Rehabilitation Purposes

2019 ◽  
Vol 292 ◽  
pp. 01010
Author(s):  
Mihailo Lazarević ◽  
Nikola Živković ◽  
Darko Radojević
Keyword(s):  
Iterative Learning Control ◽  
Control Algorithm ◽  
Closed Loop ◽  
Learning Control ◽  
Open Loop ◽  
Iterative Learning ◽  
Control Law ◽  
Exact Linearization ◽  
Outer Loop ◽  
Control Scheme

The paper designs an appropriate iterative learning control (ILC) algorithm based on the trajectory characteristics of upper exosk el eton robotic system. The procedure of mathematical modelling of an exoskeleton system for rehabilitation is given and synthesis of a control law with two loops. First (inner) loop represents exact linearization of a given system, and the second (outer) loop is synthesis of a iterative learning control law which consists of two loops, open and closed loop. In open loop ILC sgnPDD2 is applied, while in feedback classical PD control law is used. Finally, a simulation example is presented to illustrate the feasibility and effectiveness of the proposed advanced open-closed iterative learning control scheme.

An Autonomous Docking Mechanism for Vertical Lift Unmanned Aircraft

2019 ◽  
Vol 11 (6) ◽  
Author(s):  
John Papayanopoulos ◽  
Kevin Webb ◽  
Jonathan Rogers
Keyword(s):  
Measurement Errors ◽  
Closed Loop ◽  
Mechanical Design ◽  
Tracking System ◽  
Unmanned Aircraft ◽  
Wide Range ◽  
Air Vehicle ◽  
Docking Mechanism ◽  
Infrared Tracking ◽  
Autonomous Docking

Abstract Unmanned aerial vehicles are increasingly being tasked to connect to payload objects or docking stations for the purposes of package transport or recharging. However, autonomous docking creates challenges in that the air vehicle must precisely position itself with respect to the dock, oftentimes in the presence of uncertain winds and measurement errors. This paper describes an autonomous docking mechanism comprising a static ring and actuated legs, coupled with an infrared tracking device for closed-loop docking maneuvers. The dock’s unique mechanical design enables precise passive positioning such that the air vehicle slides into a precise location and orientation in the dock from a wide range of entry conditions. This leads to successful docking in the presence of winds and sensor measurement errors. A closed-loop infrared tracking system is also described in which the vehicle tracks an infrared beacon located on the dock during the descent to landing. A detailed analysis is presented describing the interaction dynamics between the aircraft and the dock, and system parameters are optimized through the use of trade studies and Monte Carlo analysis with a three degree-of-freedom simulation model. Experimental results are presented demonstrating successful docking maneuvers of an autonomous air vehicle in both indoor and outdoor environments. These repeatable docking experiments verify the robustness and practical utility of the dock design for a variety of emerging applications.

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