In machine learning, a fundamental challenge is the analysis of data to identify feelings using algorithms that allow us to determine the positive or negative emotions that people have regarding a topic. Social networks and microblogging are a valuable source of information, being mostly used to express personal points of view and thoughts. Based on this knowledge we propose a sentiment analysis of English tweets during the pandemic COVID-19 in 2020. The tweets were classified as positive or negative by applying the Logistic Regression algorithm, using this method we got a classification accuracy of 78.5%.
Abstract. This work presents the design of a bilateral tele-operation system for a mobile manipulator robot, allowing a human operator to perform complex tasks in remote environments. In the tele-operation system it is proposed that the human operator is immersed in an augmented reality environment to have greater transparency of the remote site. The transparency of a tele-operation system indicates a measure of how the human feels the remote system. In the local site an environment of augmented reality developed in Unity3D is implemented, which through input devices recreates the sensations that the human would feel if he were in the remote site, for which is considered the senses of sight, touch and hearing. These senses help the human operator to "transmit" their ability and experience to the robot to perform a task. Finally, experimental results are reported to verify the performance of the proposed system.
Purpose
This paper aims to present a unified motion control scheme for quadcopters which not only solves the point stabilization and trajectory tracking problems but also the path following problem.
Design/methodology/approach
The control problem is solved based on the kinematic model of the unmanned aerial vehicles (UAV). Next, a dynamic compensation controller is considered through of a quadcopter-inner-loop system to independently track four velocity commands: forward, lateral, up/downward and heading rate. Stability and robustness of the whole control system are proved through the Lyapunov’s method. To evaluate the controller’s performance, a multi-user application which allows bilateral communication between a ground station and the Phantom 3 PRO quadrotor is developed.
Findings
The performance of the proposed unified controller is shown through real experiments for the different motion control objectives: point stabilization, trajectory tracking and path following. The experiments confirm the capability of the unified controller to solve different motion problems by an adequate selection of the control references.
Originality/value
This work proposes the design of three types of motion controllers, which can be switched to comply a task in outdoor. Based on the software development kit provided by the company DJI, an application to get and send data to the UAV is developed. By means of this application, the three tasks are tested and the robustness of the controllers is proved.
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