Visual Localization of Mobile Robot Using Artificial Markers

AbstractThe paper presents localization method for mobile robots with use of artificial markers deployed to an environment. A specialty of the markers is that the position and rotation of the camera relative to the marker can be determined from only one marker. Further in the paper, some experiments are described. The results prove that this system can be reliably employed in visual localization of mobile robots

Path Planning with Modified a Star Algorithm for a Mobile Robot

AbstractThis article deals with path planning of a mobile robot based on a grid map. Essential assumption for path planning is a mobile robot with functional and reliable reactive navigation and SLAM. Therefore, such issues are not addressed in this article. The main body of the article introduces several modifications (Basic Theta*, Phi*) and improvements (RSR, JPS) of A star algorithm. These modifications are focused primarily on computational time and the path optimality. Individual modifications were evaluated in several scenarios, which varied in the complexity of environment. On the basis of these evaluations, it is possible to choose path planning method suitable for individual scenario

Hand guiding a virtual robot using a force sensor

The research behind this paper arose out of a need to use an open-source system that enables hand guiding of the robot effector using a force sensor. The paper deals with some existing solutions, including the solution based on the open-source framework Robot Operating System (ROS), in which the built-in motion planner MoveIt is used. The proposed concept of a hand-guiding system utilizes the output of the force–torque sensor mounted at the robot effector to obtain the desired motion, which is thereafter used for planning consequential motion trajectories. Some advantages and disadvantages of the built-in planner are discussed, and then the custom motion planning solution is proposed to overcome the identified drawbacks. Our planning algorithm uses polynomial interpolation and is suitable for continuous replanning of the consequential motion trajectories, which is necessary because the output from the sensor changes due to the hand action during robot motion. The resulting system is verified using a virtual robot in the ROS environment, which acts on the real Optoforce force–torque sensor HEX-70-CE-2000N. Furthermore, the workspace and the motion of the robot are restricted to a greater extent to achieve more realistic simulation

High Precision GNSS Guidance for Field Mobile Robots

In this paper, we discuss GNSS (Global Navigation Satellite System) guidance for field mobile robots. Several GNSS systems and receivers, as well as multiple measurement methods and principles of GNSS systems are examined. We focus mainly on sources of errors and investigate diverse approaches for precise measuring and effective use of GNSS systems for real-time robot localization. The main body of the article compares two GNSS receivers and their measurement methods. We design, implement and evaluate several mathematical methods for precise robot localization

Importance of Basset History Force for the Description of Magnetically Driven Motion of Magnetic Particles in Air

Lungs are used as an attractive possibility for administration of different therapeutic substances for a long time. An innovative method of such administration widely studied nowadays is the application of aerosolized magnetic particles as the carriers to the lungs in the external non-homogeneous magnetic field. For these reasons we have studied dynamics of such a system on a level of particle trajectory in air in the presence of magnetic force as a driving force exerted on micrometric magnetic particle. On two typical examples of magnetically driven systems—motion of magnetic particle in a gradient magnetic field and cyclotron-like motion of a charged particle in homogeneous magnetic field in microscale, where the external accelerating forces are very large and the relevant time scale is of the order from fraction of milliseconds to seconds, we have examined the importance of these forces. As has been shown, for particles with high initial acceleration, not only the commonly used Stokes force but also the Basset history force should be used for correct description of the motion

Concepts of Teleoperated Robots

This paper provides basic overview of teleoperated robotic systems and their characteristics. The aim of the paper is not to describe such robotic systems in detail such as suggesting actual hardware and software, but to provide basic information, which has to be considered during the design and usage of such robot. Paper is focused on general description of functionality, characteristics and applications of teleoperated robots. Overview of potential use cases is provided with description of potential downfalls. Means of communication with the robot are discussed and elaborated with respect to reliability and safety. Available types of human to machine interfaces and sensor systems are listed and described considering reliability, safety and quality of control. Especially safety issues are highlighted, because such robots suffer from the involvement of humans in the control scheme. This paper comes to a conclusion that it is of primary importance to consider safety measures and stresses vulnerability of whole system introduced by operator and means of communication. In this paper is further stressed that in case of lost communication teleoperated robot must be able to either safely continue its function or stop. Future research will be focused on improving teleoperation via virtual reality, further improvement of autonomous features leaving operator only to decide which actions to perform and cloud computing

Evaluation Criteria for Trajectories of Robotic Arms

This paper presents a complex trajectory evaluation framework with a high potential for use in many industrial applications. The framework focuses on the evaluation of robotic arm trajectories containing only robot states defined in joint space without any time parametrization (velocities or accelerations). The solution presented in this article consists of multiple criteria, mainly based on well-known trajectory metrics. These were slightly modified to allow their application to this type of trajectory. Our framework provides the methodology on how to accurately compare paths generated by randomized-based path planners, with respect to the numerous industrial optimization criteria. Therefore, the selection of the optimal path planner or its configuration for specific applications is much easier. The designed criteria were thoroughly experimentally evaluated using a real industrial robot. The results of these experiments confirmed the correlation between the predicted robot behavior and the behavior of the robot during the trajectory execution

Robust Control of Repeated Drug Administration with Variable Doses Based on Uncertain Mathematical Model

The aim of this paper was to design a repeated drug administration strategy to reach and maintain the requested drug concentration in the body. Conservative designs require an exact knowledge of pharmacokinetic parameters, which is considered an unrealistic demand. The problem is usually resolved using the trial-and-error open-loop approach; yet, this can be considered insufficient due to the parametric uncertainties as the dosing strategy may induce an undesired behavior of the drug concentrations. Therefore, the presented approach is rather based on the paradigms of system and control theory. An algorithm was designed that computes the required doses to be administered based on the blood samples. Since repeated drug dosing is essentially a discrete time process, the entire design considers the discrete time domain. We have also presented the idea of applying this methodology for the stabilization of an unstable model, for instance, a model of tumor growth. The simulation experiments demonstrated that all variants of the proposed control algorithm can reach and maintain the desired drug concentration robustly, i.e., despite the presence of parametric uncertainties, in a way that is superior to that of the traditional open-loop approach. It was shown that the closed-loop control with the integral controller and stabilizing state feedback is robust against large parametric uncertainties