AUTOMATION AND CONTROL TECHNOLOGICAL PROCESSES
The article considers the architecture of the ventilation control system for underground mining enterprises, equipped with a digital twin with online functions such as simulation modeling and predictive analytics. The system is focused on the main fan unit (MFU) control taking into account changing parameters of external air supplied to mine shafts. In contrast to the existing ones, the proposed method of control takes into account the influence of these parameters on changes in the total volume of natural draught, on which the total volume of air supplied to the mine (mine) depends. It is known that ventilation systems of such enterprises consume from 30 to 50 % of all electricity consumed for the mining process. In this regard, the proposed control models can be used to optimize energy costs and energy savings in ventilation. The Internet of things (IoT) InfluxData of stack TICK is offered for the realization. The offered architecture of cyber-physical system (CPS) consists of four subsystems: physical object subsystem, network and computing infrastructure IoT, digital twin, user interface. Architecture of CPS provides data processing from energy meters, control controllers and sensors of air environment parameters, implemented in blocks of on-line and off-line calculations. The digital twin of the ventilation system is made with the use of a time series database and a database of attributes that store information on changes in equipment parameters by time, air indicators, performance indicators, statistics on accidents and fan runtime, CPS characteristics, etc. CPS of the given architecture means connection of additional data sources, providing calculations of rational volumes of air delivery taking into account safety norms and requirements of energy efficiency.
ROBOT, MECHATRONICS AND ROBOTIC SYSTEMS
The probability estimation problem of a collision between path tracking for an autonomous mobile robot with an obstacle is considered. We reviewed and analyzed methods for solving this problem. We show that reviewed methods use periodically updated grid maps (occupancy grids). The new method of probability estimation of the collision between the mobile robot with an obstacle is presented. This method based on the use of probabilistic grid map. Each cell of this map stores the estimated probability that the obstacle is located within. In addition, this map stores the conditional probability of occupying of the map cells by a robot, taking into account the possible lateral and angular deviation from the planned trajectory. This deviation caused by error connected with dynamic characteristics of the tracking system. To build the probabilistic occupancy grid, the dynamically updated multilayer grid map was used. Each layer of this map, except for the resulting output, has been filled with the data obtained from classifiers which process information incoming from sensory of the robot. This layer is the result of Bayesian inference from the layers laying below. The motion control system provides construction of the multilayered grid maps, probabilistic occupancy grids, coordinate estimations, path planning, motion tracking and the probability estimation for collision with obstacles. The method such estimation is implemented as an embedded module compatible with ROS (Robot Operating System). The description of experiments with the mobile robot in-nature (on the field) is given in the case when a motile obstacle appears intercepting the planned path. The estimated changes of probability for a collision between the mobile robot with obstacle are presented, interpretation of the obtained results is also given. Here we demonstrated the necessity of collision probability estimation for assessment of the risk as the main safety indicator of the given motion control system. Results of this work are considered and evaluated as a solution to the problem of ensuring the safety of motion tracking for autonomous mobile robots.
Currently, autonomous underwater vehicles (AUV) are increasingly used to perform tasks related to the maintenance of underwater communications and various underwater production complexes, as well as performing underwater technological operations. To effectively perform these operations, AUV must have high-quality control systems that will ensure their accurate movement both along long spatial trajectories formed during their movement to the objects of work, and when performing complex maneuvers near underwater infrastructure objects. At the same time, the main difficulty that arises in the process of synthesis of AUV control systems is the significant non-linearity of the dynamic models of these control objects, the presence of interactions between their degrees of freedom, as well as the uncertainty and variability of their parameters. In this paper, we propose a method for synthesizing the spatial motion control system of the AUV, which allows us to take into account these negative effects. This system contains two loops. The first loop includes a combined system containing a nonlinear controller to achieve the desired dynamic characteristics of the AUV, when its parameters are equal to the nominal values, and a controller with self-tuning according to the reference model, which provides compensation for an unknown or variable part of the parameters. In this case, the parameters of the controller with the reference model are selected to reduce the possible amplitude of the discontinuous signal for controlling the AUV velocity. The second loop is a non-linear position controller that allows to take into account the dynamic properties of the velocity control loop and the kinematic properties of the AUV. The advantage of the proposed control system in comparison with traditional ones based on PID controllers is a higher control accuracy when moving along complex spatial trajectories, regardless of changes in the AUV parameters. The simulation results confirmed the high efficiency of the synthesized two-loop control system.
The major point for consideration throughout this paper is controlling the motion of an unmanned powerboat in an obstructed environment with stationary and moving objects. It offers a procedure for the terminal control law development based on the powerboat programmed motion trajectory in a polynomial form and proposes position-trajectory-based control algorithms. A hybrid method based on virtual fields and unstable driving modes, taking into account powerboat speeds and obstacles, is used to plan motion trajectories for obstacle avoidance. There were experiments carried out to test the developed methods and algorithms meanwhile estimating the energy consumption for control, the length of the trajectory and the safety indicator for obstacle avoidance. The novelty of the proposed approach lies in the method used to develop a local movement trajectory in the field with obstacles and in the hybridization of trajectory scheduling methods. This approach allows us to achieve a given safe distance when avoiding obstacles and virtually eliminate the chances of an emergency collision. The presented results can be used in systems of boats autonomous motion control and allow safe stationary and dynamic obstacles avoidance.
DYNAMICS, BALLISTICS AND CONTROL OF AIRCRAFT
The final and one of the most important stages of the aircraft-type unmanned aerial vehicles (UAV) flight is landing. In this regard the problem of automating the control by UAV landing in difficult meteorological conditions is becoming increasingly urgent. In some cases for refueling and recharging UAVs it is advisable to use the dynamic mobile landing site (MLS) instead of the traditional stationary landing site (SLS). In the present paper we consider the setting of and solution of the control problem by the terminal landing maneuver of a UAV. It provides its transfer from the current initial state to the target final state along " flexible" kinematic trajectories both on the SLS and on the MLS. To solve the problem of automatic landing of UAV on SLS or MLS the mathematical model of the dynamics of its movement was developed. It’s based on the concept of " flexible" kinematic trajectories with spatial synchronization of controlled movements. The control algorithm by the terminal vertical landing maneuver of UAV on SLS by the method of dynamics inverse problem using the principle of " flexible" kinematic trajectories is developed. And also the control algorithm by the terminal landing maneuver of UAV on MLS by the method of dynamics inverse problems using the principles of " flexible" kinematic trajectories and aiming into the target point was also developed. Computer approbation of the synthesized control algorithms for the landing maneuver of UAV "Aerosonde" under conditions of various wind disturbances was carried out using digital modeling in the Matlab environment.
ISSN 2619-1253 (Online)