Michał Siwek

This paper considers the problem of flying a UAV along a given trajectory at speeds close to the speed of sound and above. A novel pitch channel control system is presented using the example of a trajectory with rapid and large changes in flight height. The control system uses a proportional–integral–differential (PID) controller, whose gains were first determined using the Ziegler-Nichols II method. The determined gains were then optimised to minimise height error using a recurrent back-propagation neural network (PIDNN), with which new controller gains were determined, which is also a novelty of this study. Simulations were carried out for flights at subsonic speeds close to the speed of sound and supersonic speeds, at low and high altitudes. The simulations showed that determining controller gains using a recurrent neural network significantly minimises height errors and increases the flexibility of the PID controller.

The development and study of an optimal control method for the problem of controlling the formation of a group of mobile robots is still a current and popular theme of work. However, there are few works that take into account the issues of time synchronization of units in a decentralized group. The motivation for taking up this topic was the possibility of improving the accuracy of the movement of a group of robots by including dynamic time synchronization in the control algorithm. The aim of this work was to develop a two-layer synchronous motion control system for a decentralized group of mobile robots. The system consists of a master layer and a sublayer. The sublayer of the control system performs the task of tracking the reference trajectory using a single robot with a kinematic and dynamic controller. In this layer, the input and output signals are linear and angular velocity. The master layer realizes the maintenance of the desired group formation and synchronization of robots during movement. Consensus tracking and virtual structure algorithms were used to implement this level of control. To verify the correctness of operation and evaluate the quality of control for the proposed proprietary approach, simulation studies were conducted in the MATLAB/Simulink environment, followed by laboratory tests using real robots under ROS. The developed system can successfully find application in transportation and logistics tasks in both civilian and military areas.

The paper presents the identification process of the mathematical model parameters of a differential-drive two-wheeled mobile robot. The values of the unknown parameters of the dynamics model were determined by carrying out their identification offline with the Levenberg-Marguardt method and identification online with the Recursive least-squares method. The authors compared the parameters identified by offline and online methods and proposed to support the recursive least squares method with the results obtained by offline identification. The correctness of the identification process of the robot dynamics model parameters, and the operation of the control system was verified by comparing the desired trajectories and those obtained through simulation studies and laboratory tests. Then an analysis of errors defined as the difference between the values of reference position, orientation and velocity, and those obtained from simulations and laboratory tests was carried out. On itd basis, the quality of regulation in the proposed algorithm was determined.

The article presents issues related to an experimental study of the vibrations of a roller shutter gripper on a robotic palletizing station. The authors presented the developed and built construction of the gripper for handling whole layers of products, separators, and pallets. The concept of the device was developed in cooperation with an integrator company. The authors verified the functionality of the gripper in a virtual environment for modeling and programming industrial robots. After the gripper was manufactured and the control software was developed for it, functional tests and inertia tests were carried out. The main purpose of the tests was to determine the vibration of the robot’s flange and the vibration of the attached gripper. Tests of the gripper’s properties on the robotic test bench were performed using MTi XSENS sensors and a PHANTOM V210 high-speed camera. The testing methodology proposed by the authors made it possible to confirm the occurrence of vibrations in the structure and to determine the relationship between the parameters of the robot’s motion (velocity and acceleration) and the magnitude of the vibrations occurring. During the tests, a disturbance in the decrease in the maximum value of acceleration was noted. This may be due to the appearance of natural vibrations in the structure. They have a damped character; however, they are not steady. In future work, the authors will focus on the possibility of using the proposed methodology to reduce robot vibrations in selected robotic production processes (such as spot welding).

The paper presents the step by step process of modelling the movement of dispersed group of mobile robots using the MATLAB Simulink and Simscape Multibody software. As a modelled object, a group of laboratory robots, TurtleBot2, was adopted. First, the construction of a robot CAD model was described. Next, the control system developed in Simulink was described. At the end, the robot components were defined in Simscape Multibody and a group movements analysis was carried out.

The article presents a concept of building modular mobile robot, designed for the inspection and engineering works, in particular installation of fibre-optic cables. The authors present both the technical problem and one of concepts showing how to solve it. The assumptions adopted for development of the robot include possibility of changing the kinematic structure of the robot in order to provide possibility of working in sewers with a diameter range of 200-800 mm.

The main aim of the paper is to present the process of design pipe inspection mobile robot by using 3D simulations. Next methods and processes of making designed components was described. Finally, functional tests of a constructed real robot model such as speed tests, inclined pipe test was carried out. The robot was specifically designed to inspect sewer pipelines. The mobile robot is equipped with a vision system. The structure of the pipe inspection robot allows adjustments to the geometrical parameters of the robot to suit the sewer pipes diameters by using in the construction of a pneumatic system with an actuator.