This paper describes the development of Pathfinder - an autonomous guided vehicle (AGV) intended for the transportation of material in hospital environments. Pathfinder is equipped with the latest industrial hardware components and employs the most recent software stacks for autonomous localization, navigation and mapping. As the most significant contribution to the current robotics development, Powerlink interface enabling direct data transfers between Robot Operating System (ROS) and Powerlink compatible hardware was developed. This combination is in our best knowledge reported here for the first time and the results with comprehensive tutorial were made publicly available as a Github repository. The capabilities of Pathfinder were explored during preliminary on-site tests in local hospital. From experimental results in a hospital it was confirmed that the robot can move along its global path, and reach the goal without colliding with static and moving objects.

This paper describes the development of Phollower—an autonomous mobile robot intended to perform various logistical tasks in both industrial and civil environments. Phollower is equipped with the latest types of industrial components and sensors. It also employs advanced embedded navigation and localization software to create its own virtual maps and thereby to navigate autonomously within the mapped area. The whole development process has been focused on building a device that meets European safety standards. Phollower is a universal mobile platform that can be quickly expanded with specialized add-ons. A germicidal add-on for disinfection of indoor areas using UV-C light is described as a technology that helps to battle with the ongoing COVID-19 pandemic crisis. The hardware topology combined with the proposed open Programmable Logic Controller (PLC) code and open-Powerlink communication bus creates a unique and easily extendable robot platform.

In the modern high-performance drive applications, a high-precision and efficient control of the induction motor depends on the accuracy of parameter values. However, the motor parameters may change due to the winding temperature fluctuations, flux saturation and skin effect. Any discrepancy between the values of the motor’s actual parameters and the ones used for the design of the controllers may result in degradation of the drive performance. In this work, a new identification method of hardly measurable internal quantities of the induction motor, such as components of the magnetic flux vector and electromagnetic torque, is outlined. Commonly, the measurable quantities of the induction motor like stator currents, stator voltage frequency and mechanical angular speed are used to determine a feedback effect of the rotor flux vector on the vector of the stator currents of induction motor. Based on this feedback, it is also possible to identify the actual value of the rotor resistance, which may alter during the induction motor operation. This has a significant impact on the precision of the identified quantities as well as on the master control of the induction motor. Stability of the identification structure is guaranteed by the position of roots of characteristic equation of its linear transfer function. Simulation and experimental results are given to highlight the quality, effectivity, feasibility, and robustness of the proposed identification method, which is working reliably within the whole range of the motor angular speed.

The article describes design and experimental verification of a new control structure with reference model for a multi-motor drive of a continuous technological line in which the motors are mutually mechanically coupled through processed material. Its principle consists in creating an additional information by introducing a new suitable state variable into the system. This helps to achieve a zero steady-state control deviation of the tension in the strip. Afterwards, the tension controller is designed to ensure asymptotic stability of the extended system by applying the second Lyapunov method. The realized experimental measurements performed on a continuous line laboratory model confirm the advantages and correctness of the proposed control structure: it is simple, stable, robust against changes of parameters, invariant to operating disturbances and ensures a high-quality dynamics of the controlled system prescribed by the reference model. To demonstrate effectiveness of the design, the performance of the controller was compared with properties of a standard Proportional Integral Derivative/Proportional Integral (PID/PI) controller designed in frequency domain.