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Practical aspects of design and testing unmanned aerial vehicles

Szywalski Patryk, Waindok Andrzej

Acta Mechanica et Automatica

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2020

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Vol. 14, no. 1

50--58

EN

A design of an unmanned aerial vehicle (UAV) construction, intended for autonomous flights in a group, was presented in this article. The design assumptions, practical implementation and results of the experiments were given. Some of the frame parts were made using 3D printing technology. It not only reduces the costs but also allows for better fitting of the covers to the electronics, which additional-ly protects them against shocks and dirt. The most difficult task was to develop the proper navigation system. Owing to high costs of preci-sion positioning systems, common global positioning system (GPS) receivers were used. Their disadvantage is the floating position error. The original software was also described. It controls the device, allows performing autonomous flight along a pre-determined route, anal-yses all parameters of the drone and sends them in a real time to the operator. The tests of the system were carried out and presented in the article, as well.

2

Reinforcement Learning in Discrete and Continuous Domains Applied to Ship Trajectory Generation

Rak A., Gierusz W.

Polish Maritime Research

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2012

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S 1

31-36

EN

This paper presents the application of the reinforcement learning algorithms to the task of autonomous determination of the ship trajectory during thein-harbour and harbour approaching manoeuvres. Authors used Markov decision processes formalism to build up the background of algorithm presentation. Two versions of RL algorithms were tested in the simulations: discrete (Q-learning) and continuous form (Least-Squares Policy Iteration). The results show that in both cases ship trajectory can be found. However discrete Q-learning algorithm suffered from many limitations (mainly curse of dimensionality) and practically is not applicable to the examined task. On the other hand, LSPI gave promising results. To be fully operational, proposed solution should be extended by taking into account ship heading and velocity and coupling with advanced multi-variable controller.

3

Integration of vision based image processing for multi-axis CNC machine tool safe and efficient trajectory generation and collision avoidance

Ahmad R., Tichadou S., Hascoet J.-Y.

Journal of Machine Engineering

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2010

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Vol. 10, No. 4

53--65

EN

Demand of high speed production not only increases the complexity of today's CNC process, but also increases the risks and possibility of collision because of the difference between real (machining) and virtual scenes (CAD/CAM process). Idea here is to make this process more intelligent by processing image taken from the real or virtual machine scenes. Identify objects (already known in the CAD database), obtain safe and efficient trajectories that will modify the previous known trajectories from the CAM systems and will be used finally in real machining environments. This work more focuses to improve trajectory generation, collision avoidance and communication in CAD/CAM systems by image processing technique. Safe and Efficient Trajectory (SET) algorithm for point trajectory is discussed along with its extended version for object trajectory known as Rectangular Enveloped object Safe and Efficient Trajectory (RESET) algorithm that will perfectly generate safe un-functional trajectories [3] for multi-axis machine tool envelop. Meanwhile scene objects are detected and identified by image processing tool while trajectory and setup is optimized and improved accordingly in order to avoid collision. This generated trajectory can be used for setup correction before and after production or for "real times/online" production. Finally work has been validated through real and virtual machine scene images.

4

NTGsim: A graphical user interface and a 3D simulator for nonlinear trajectory generation methodology

Di Trapani L. J., Inanc T.

International Journal of Applied Mathematics and Computer Science

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2010

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Vol. 20, no 2

305-316

EN

Nonlinear Trajectory Generation (NT)), developed by Mark Milam, is a software algorithm used to generate trajectories of constrained nonlinear systems in real-time. The goal of this paper is to present an approach to make NTG more userfriendly. To accomplish this, we have programmed a Graphical User Interface (GU)) in Java, using object oriented design, which wraps the NTG software and allows the user to quickly and efficiently alter the parameters of NTG. This new program, called NTGsim, eliminates the need to reprogram the NTG algorithm explicitly each time the user wishes to change a parameter.

5

Path tracking by the end-effector of a redundant manipulator

Galicki M.

Archives of Control Sciences

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2001

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Vol. 11, no. 3/4

245-261

EN

This study deals with the problem of tracking a prescribed geometric path by the end-effector of a kinematically redundant manipulator at the control-loop level. During the robot motion, the control constraints resulting from the physical abilities of robot actuators are taken into account. The Lyapunov stability theory is used to derive the control scheme. The numerical simulation results carried out for a planar manipulator whose end-effector tracks a segment line in a two-dimensional work space, illustrate the trajectory performance of the proposed control scheme.