Comparative analysis of digital data conversion algorithms in NC systems of machine tools

The research is aimed at studying the selection of instruments to encode, convert and compress digital data for various purposes. Hardware and software approaches to data conversion are considered. Two approaches are distinguished and described among many hardware realizations as most suitable for control systems - matrix-based and pulse-counting methods and corresponding circuits, with their advantages and disadvantages highlighted. Software-based algorithmic solutions are recommended as providing more flexible, reliable, compact and fast-response functioning in many aspects. Computational and table-based software algorithms for NC systems of machine tools (lathes and mills) are analysed and compared using a computer program developed for that purpose. The analysis is aimed at checking whether the differences between the algorithms are significant and finding an algorithm which would provide a higher operation speed in control systems of lathes and mills. The computational algorithm is concluded to be more suitable for NC systems of those machine tools, but it is stressed that the table-based method is more appropriate for certain purposes and applications. © 2021 Author(s).Ministry of Education and Science of the Russian Federation, Minobrnauka, (075-02-2022-877)Russian Science Foundation, RSF, (21-71-00044)The present research work consists of theoretical and computational parts, which were supported by different financial sources. E.A.T. acknowledges the Russian Science Foundation (Project No. 21-71-00044) for the development of the boundary integral method. L.V.T. is grateful to the financial support from the Ministry of Science and Higher Education of the Russian Federation (Project 075-02-2022-877 for the development of the regional scientific and educational mathematical center “Ural Mathematical Center”) for the development of the selection criteria, computer simulations, and numerical examples

On selection of optimal stop position and spatial orientation of mobile robot

The paper analyses the problem of finding optimal coordinates of a mobile robot equipped with a manipulator. An optimization criterion is proposed and validated, and a method for calculating most rational coordinates of the robot is described. © Published under licence by IOP Publishing Ltd

Informative modeling of subjective reality for intellectual anthropomorphic robots

This research is aimed at solving the problem of safeguarding robot operation by modeling the subjective reality of an intellectual anthropomorphic robot. Analysis has been carried out on trends in designing advanced robot control systems and methods of improving the safety of robot usage. The following conclusions are drawn: the risk of causing damage to human life, health or property increases when people interact with robots; it is necessary to combine neural network control systems with expert control systems in order to enhance the intellect of a robot and raise the level of trust held by humans towards robots; developing norms and regulations, designing collaborative robots, drawing visualization diagrams for safety zones cannot really provide the depth of robot socialization sufficient for the human society; an informative model of the subjective reality could be integrated into an intellectual anthropomorphic robot to provide a safer 'human-robot' interaction. Such an approach should result in achieving the greatest trust of humans and their safety due to anthropomorphic conversion of both the external design of a robot and its internal control structure. By its nature, the research is interdisciplinary - it is run in the fields of artificial intelligence and philosophy of subjective reality. © Published under licence by IOP Publishing Ltd

Increasing power efficiency of open-pit excavators

It is shown that a working process of rock excavation realized by an open-pit front-shovel excavator is characterized by an increased power intensity due to counteraction of its main actuating mechanisms (lifting and thrusting), whose operational parameters have to be properly matched during their joint action to provide more efficient excavation. A computational experiment allowed to determine an actual work of lifting and thrusting forces immediately involved in developing an excavated face. It was further established that power inputs depend on the bucket position relative to the working area of an excavator, and such regions of that area where those inputs are higher were determined. Differentiated calculation of the inputs was carried out, based on the type of a conducted operation-power inputs originating from excavating, from counteraction of the main mechanisms, and from lifting operational equipment parts and rock. The power intensity of excavation was estimated for various regions of the workspace of the excavator. The proposed method for calculating the power inputs of rock excavation using the operational equipment of an open-pit excavator would allow to determine an energy characteristic of the excavator for specific mining and technical conditions of operation. © Published under licence by IOP Publishing Ltd

Specifics of drives functioning in main mechanisms of open-pit excavator

Specifics of functioning for the drives of main (lifting and thrusting) mech-anisms in an open-pit excavator were determined for their joint action during the process of excavation. It was shown that the operation forms a two-crank lever-age transmission mechanism (connecting the main mechanisms and the excavator bucket) and a common transmission mechanism of the drives (consisting of the main mechanisms and the leverage). It was also established that an initial link of the common transmission mechanism would be a stick-bucket link whose co-ordinates determine positions of every other link in the mechanism in relation to the stand (a boom). Dependencies were derived for finding kinematic transfer functions of the leverage, that is relations between lifting and thrusting velocities and an excavation velocity when the bucket (its cutting edge) is moved along a given trajectory in the process of pit development. The results of the research could be used for the purposes of designing a control system for the main drives of an excavator. © Published under licence by IOP Publishing Ltd

Development of algorithm for excavation control

In open-pit excavators there exists a discrepancy between their engineering designs and underuse of performance potential due to complexity of excavation and such intensity of carrying out working procedures which borders on physical limits of an operator. The excavating procedure is shown to involve joint functioning of main actuating mechanisms of an open-pit excavator for its thrusting and lifting operations and formation of a leverage transmission mechanism connecting those with a bucket. In that case, it was established, the excavation process is characterized by a 'conversion' of the main mechanisms since their operation parameters are formed according to kinematic properties of the leverage and energy-force parameters realized on the bucket. Dependencies were derived to calculate kinematic transfer functions of the leverage, which correlate the velocity of excavation and those of working motions (speeds of thrusting and lifting). The algorithm of calculating the velocities of working motions could be used to develop a digital system to control the motors of the main mechanisms. © Published under licence by IOP Publishing Ltd