METHOD FOR CALCULATING CUTTING FORCES BY MODELING CAD WITH A SYSTEM OF GEOMETRIC CUTTING PARAMETERS WITH RADIAL MILLS

The accuracy of processing surfaces of a complex profile largely depends on the selected processing strategy, which will allow creating the same, within certain limits, power characteristics of the shaping process at the intervals of the programmed tool path. In this case, it becomes possible to include tuning modules in programs for CNC machines that form vector values of corrections in certain areas, as reactors for elastic deformations of the cutting process. Therefore, it is especially important to know the modulus and direction of the resulting cutting force vector, which does not necessarily coincide with the feed direction. The purpose of this work is to build a method for calculating cutting forces by modeling the geometric parameters of a cut with a CAD system, a cutter with a nonlinear generatrix. Solid modeling of the process is based on the Boolean operations of "intersection" and "subtraction" of 3D objects: the teeth of a radius cutter with a helical cutting edge and a workpiece "moving" at a feed rate. The tool for the implementation of this method is a software module created on the basis of API functions, the input data for which are: a 3D tool and a workpiece, the equation of the trajectory of its movement and the parameters of the infeed movement. Targeting API properties, the application makes it possible to simulate various trajectories, helical or trochoidal, when machining complex surfaces. In the future, it is possible to take into account the plastic deformation processes in the chip formation zone in the model by connecting external modules. In the course of the conducted research on milling with radial end mills with a helical cutting edge, when two or more teeth are within the arc of contact, it was determined by 3D modeling how much thickness and width the layer cuts off each of the teeth during the feed per revolution. Consequently, in the process of shaping, normal and tangential cutting forces, which are different in direction and modulus, are present as a function of the angle of rotation of the cutter. Therefore, the concept of "circumferential force on the cutter", accepted in the theory of cutting, as a certain constant component of the process, can introduce an error when considering the causes of the excitation mechanism of vibrations of different nature that arise in the processing zone.

HARDWARE AND SOFTWARE OF AUTOMATIC CONTROL SYSTEM OF FUEL COMBUSTION PROCESS IN LOW AND MEDIUM POWER BOILERS. PART 2. ALGORITHMIC SOFTWARE

The efficiency of the functioning of boiler units depends on the availability of reliable information on the progress of technological processes. The lack of control and measuring systems for the composition of the exhaust gases leads to low efficiency of the boiler unit, in particular, due to poor-quality fuel combustion. Therefore, in modern operating conditions of boiler units, it is relevant to develop technological solutions focused on finding and minimizing the causes and mechanisms of the formation of harmful substances in exhaust gases. Due to the fact that replacement of outdated boiler units with new ones requires significant capital investments, a promising direction is the modernization of existing boiler units. It is a low-cost and efficient way of rational use of fuel while simultaneously reducing the level of harmful substances in exhaust gases. It remains relevant to ensure the functioning of the control systems for the composition of the air-fuel mixture (AFM) with a given speed and high reliability of maintaining the excess air ratio (EAR) at the stoichiometric level. In the article the high-quality algorithm is proposed for the operation of an automatic control system for the combustion of fuel in boilers of medium and low power by regulating the ratio of the components of the AFM for the burner with feedback according to the signals of the oxygen sensor. The algorithms for the operation of the frequency regulator of the ratio of the components of the AFM in various operating modes are considered. The developed algorithms allowed maintaining the stoichiometric air-fuel ratio in the boiler furnace, reducing the level of toxic emissions into the atmosphere and increasing the boiler efficiency by optimizing the fuel combustion process. The AFM ratio programmer is made in the LM Programmer technical programming environment and works with Windows operating systems (XP, Vista, 7, 8, 10) and oxygen sensors manufactured by Bosch. The visualization of the control process of the fuel combustion process is made in the technical programming environment LogWorks 3 and operates in the environment of Windows operating systems.

INVESTIGATION OF THE UNCERTAINTY VALUE AT MEASURING THE TEMPERATURE OF THE COOLANT IN THE PIPELINES WITH OUTSIDE SURFACE MOUNTED TEMPERATURE SENSORS

During performing technological and production processes and monitoring the modes of their operation, the problem of determining the temperature of various media transported through pipelines is solved without incut temperature sensors (TS) in them, i.e. with using outside surface mounted TS (SMTS). This method is allowing to measure mechanical values at technological processes without structure broken and without influence to physicochemical properties of measured media. Using of SMTS possible to register heat losses on sections of heating mains, pollution degree of pipelines internal walls, to control serviceability of measurement channels of temperature of the coolant in heat meters, etc. In the article authors presents results of research the uncertainty values for measuring of the coolant temperature in heating systems pipelines under different modes of its flow. First of all, the uncertainty value of the measurements results was estimated, which was determined by the results of the study for the calculation model and field tests at existing district heating systems. Emphasis is paid on estimating the difference between the registration of temperature in the middle of the pipeline, determined by mortise transducers and the temperature measured by outside surface mounted temperature transducers, taking into account the temperature gradient across the pipeline and the quality of its insulation. It is determined that: the temperature measured by temperature transducers on the surface of the pipeline at different points of its perimeter, with proper installation and sufficient thermal insulation does not depend on their location; the average temperature on the surface of the pipeline, measured using the developed method of installation of PT, slightly differs (ΔT ≈- 0.3⁰C) from the average temperature of the coolant in the middle of the flow; temperature transducers have high reproducibility of measurements and small difference in readings between channels at parallel measurements (»0,03⁰С). It is substantiated that high metrological performances of temperature transducers allow to use them for solving other tasks: measuring the distribution of heat fluxes in heating systems of residential buildings to perform hydraulic balancing of heating systems and increase their efficiency; estimate of contamination of pipelines and heat exchange equipment to determine the need for their washing; determination of thermal resistance of buildings protective structures to assess their energy efficiency; determination of large pumps efficiency by calorimetric method; checking the correct of operation the temperature measuring channels of heat meters and cold meters; in other technology areas where measurements of small temperature differences with high accuracy are required.

STRUCTURAL AND PARAMETRIC OPTIMIZATION OF GAS-HYDRODYNAMIC MEASURING TRANSDUCERS OF PHYSICAL AND MECHANICAL PARAMETERS OF FLUIDS

The article is devoted to improving the methods for building throttle diagrams of gas-hydrodynamic measuring transducers of physical and mechanical parameters of fluids. The authors reviewed modern throttle transducers of various parameters, built on different diagrams, with different numbers and types of throttle elements, with different output signals. We established that the goodness of the measuring transducer is determined both by the structural diagram and the design characteristics of the throttle elements of a specific measuring diagram. The article proposes using structural synthesis with parametric optimization to achieve the specified characteristics of the gas-hydrodynamic transducers. The aim is to develop an effective method for building throttle diagrams of gas-hydrodynamic measuring transducers of physical and mechanical parameters of fluids using structural optimization of diagrams and to evaluate each dia-gram using parametric optimization methods with the appropriate criterion that quantifies the goodness of the measur-ing transducer. To achieve this goal, the authors analyzed the criteria and resources of structural and parametric optimization of gas-hydrodynamic transducers. In particular, the following resources of structural synthesis of measuring transducers’ dia-grams are analyzed: diagram order and throttle arrangement, type of throttles, output signals, supply mode of the transducer. Approaches to parametric optimization of throttle diagrams are offered: based on the mathematical model, one defines the objective function, forms restrictions on variable and fixed values, substantiates optimization parameters, chooses the optimization method. As a result of the research, the authors developed a technique for structural and parametric optimization of gas-hydrodynamic measuring transducers, making it possible to synthesize throttle diagrams and build mathematical models of transducers of specific parameters of the fluid with optimal characteristics.

HEXAPOD MOVEMENT ALGORITHMS TO AVOID INTERFERENCE. ANGULAR MOVEMENT

This paper considers the possibility of using a stepping robot - hexapod for research, monitoring the condition of technical dry channels, enclosed spaces and more. Compared to existing designs used today, the hexapod has a list of advantages that make it a more versatile tool, namely: autonomy, due to the power supply installed at work, design features that ensure its increased patency on uneven surfaces. Instead, this type of work requires the development of complex algorithms for movement than in the case of wheeled or tracked machines, ie. hexapod is a platform that moves the limbs, which in turn move with the help of servos. Therefore, the movement of the platform is provided by the control of each servo. In addition, environmental information is additionally processed from rangefinders, limb con-tact sensors with the surface, cameras, accelerometers, etc. Particular attention is paid to robot rotation algorithms, as the proposed scope imposes restrictions on the ability to maneuver freely in space. An algorithm for rotating robots in confined spaces based on limb state matrices has been developed, which greatly simplifies the practical implementation and allows to easily change the type of stroke during the hexapod operation. It is also proposed to introduce a buffer state matrix, which allows you to remember the last position of the limbs of the robot in case of its failure, after the elimination of which, it is possible to continue moving from any last state. Or return to the starting position and change the route. The versatility of the algorithm allows its use not only in the development of the software part of the hesapod, but also for other types of walking robots. Since the developed algorithm allows you to easily modify the types of moves at each iteration of the step. In the future, it is planned to test this algorithm on a model of a hexapod and supplement it with the necessary components for vertical movement, which is very important for passability in this area of application.

LAND UNMANNED COMPLEX WITH PASSIVE RANGE MEASUREMENT

The automatic robotic complex will obviously become one of the main subjects in the conduct of military actions in the near future. To control movement parameters, as well as search, target detection and aiming, the complex includes a technical vision system. The minimum sufficient configuration of such a system includes a television search camera with a wide field of view, television and thermal imaging sights, and a rangefinder. The use of laser rangefinders ensures high accuracy of aiming weapons, but generates a powerful unmasking feature. To ensure the secrecy of the functioning of the robotic complex, range finders can operate in a passive mode using information from on-board television cameras. But at the same time, the metrological characteristics of the information measuring channel are significantly deteriorated. Accuracy of five methods of passive distance measurement with application of TV-systems of land unmanned complex is assessed in paper. Classic method of TV-sight external-base range-finder with scale, designed on human height 1,65 m, is ensuring measurement accuracy 135 m on distance 1000 m. External base method, when a range finger scale is forming on remote display as variable length vertical line in process of target framing, is ensuring measurement accuracy 100,3 m on dis-tance 1000 m. Fixed-base range-finder method, when distance between entrance pupils of TV-sight and wide viewing field camera using as base, is ensuring measurement accuracy 76 m on distance 1000 m. Distance measurement method due to displacement of land unmanned complex ensures a measurement accuracy up to 168 m on distance 1000 m. Measurement method due to using zoom-objective is not suitable for land unmanned complex. Proposals have been formulated for the spatial layout of the computer vision system, in which the method of the fixed-base rangefinder is implemented, which ensures the highest measurement accuracy.

DETERMINATION OF THE ACOUSTO-OPTICAL DEFLECTOR PARAMETERS FOR A LASER-RADIATION ROCKET GUIDANCE SYSTEM

The work is devoted to the development of an acousto-optic deflector for a laser-beam guidance system (LLSN) of missiles. LLSN is used in semiautomatic portable missile systems to destroy hostile targets of various types. An analysis of the methods for constructing such systems has shown that the most promising devices with pulse-code modulation using semiconductor pulsed lasers. The article provides a diagram and describes the principle of operation of the LLSN with pulse-code modulation. A problematic issue in the implementation of such a system is the development of a device for deflecting a laser beam, through which the missile is guided to a target. Scanning mechanical devices that are currently in use have a complex design, significant dimensions and weight, and limited performance. The article proposes to use an acousto-optic deflector to deflect the laser beam within the information field of the guidance system, which is devoid of these disadvantages, since it replaces the mechanical scanning device with an electronic one. The purpose of the article is to determine the main parameters of the acousto-optical deflector. The article discusses the principle of operation of an acousto-optic deflector. It is noted that glasses based on germanium chalcogenides, in particular, glass with the composition Ge2.17As39.13S58.70, have especially low values of acoustic losses (α <1 dB / cm). The largest deflection angle of the laser beam will be observed with Bragg diffraction. Relationships are given that can be used to determine the main characteristics of the deflector: the angle of deflection of the laser beam, the modulation frequency of the acoustic wave, resolution, speed, and others. When using the above ratios for the typical parameters of the existing guidance system, the values of the indicated characteristics are calculated.

THEORETICAL FUNDAMENTALS OF THE CALCULATING THREE-MIRROR DECENTER ANASTIGMATS METHODOLOGY

The article is devoted to the theory of calculating mirror systems with anastigmatic properties, namely, the area of research in terms of developing methods for parametric calculation of dimensions and aberration correction. The such systems can correct three third-order aberrations. Mirror anastigmats allow developing the angular field of view of devices while maintaining a high numerical aperture, which allows them to be used in optoelectronic equipment operating in a wide spectral range. Complete absence of chromatic aberrations, high resolution, permissible wave criteria for image quality provide excellent opportunities for using mirror anastigmatic systems. General methodological approaches have been developed that can be applied to the creation of detailed engineering and technical methods for calculating a group of mirror anastigmatic systems. A serious drawback of reflective optics is center without central screening, which degrades image quality. To eliminate it, rotations or displacements of the mirrors are intro-duced, but non-elementary aberrations of even orders appear, which must be corrected. The creation of compositions with decentered catoptric elements requires further development of the calculation and methodological base. Mathematical solutions to the problem of creating basic models of non-centered mirror systems are presented. Accurate formulas are obtained for the calculation of real rays from the conditions of astigmatism and coma correction for the given angles of incidence of the chief ray on the mirror surfaces and the «oblique» thickness , which determines their relative position. Based on the proposed formulas, a new method for parametric calculation of decentered mirror systems has been created, which allows one to compose algorithms and design both basic models and complex mirror systems from off-axis mirrors. The development of new algorithms for two- and three-mirror decenter lenses will increase the accumulated potential of computational optics. The scope of the proposed technique can be expanded in terms of the number of components.

BIOIMPEDANCE ANALYSIS IN THE DIAGNOSIS OF SKIN CONDITION

The number of visits and calls to doctors with dermatological diseases is growing rapidly every year and every year the number of cases with malignant skin tumors increases catastrophically. In medical practice, the diagnosis of any skin disease occurs by a doctor in several stages: history taking, visual examination with percussion and palpation, referral to the laboratory, if it is really necessary, for additional examination and diseases differentiation. The last stage is the most expensive due to the duration of the analysis process time, and with malignant neoplasms - this is a very critical factor because it affects the effectiveness of the further treatment and survival chance. In addition, without the conclusion of the laboratory and tests to provide recommendations for specialized treatment is almost impossible, because the doctor being in the dark and should act more at random, not at instructions with accurate information and diagnosis. Given this, there is a need for diagnostic tools that will allow dermatologists to quickly and by hand differentiate pathological conditions. The aim of this work is to find significant differences in the values of capacity and impedance of healthy tissues and tissues with cancers of varying severity, lesions, and dislocations. The founded differences can be used to predict and diagnose malignancies and cancer of the upper layers of the skin. Based on the results of experiments, an impedance analyzer of the state of biological tissue is proposed for use, the structural scheme and principle of operation of which is illustrated in the work. The results of this study can serve as a key factor and starting point in the future expansion of the tools of dermatological offices, in order to improve the efficiency of rapid diagnosis and identification of dermatological diseases, without waiting for the results of histological examinations.

INFLUENCE OF OBJECT TECHNOLOGICAL PHANTOM’S TRANSFORMATIONS OF THE PRODUCTION’S QUALITY

The article states that the relevance of modeling processes, followed by analysis of the features of the transformation of the technological phantom of the real object, in particular precision instrumentation products, which affects the accuracy of shaping the formation of this object in automated production. The main purpose of this study was to substantiate analytical models of transformations of the technological phantom of the object, taking into account the type of coordinate systems, which can be observed transformation of some coordinates into others. These features of the transformations significantly affect the accuracy of the formation of this object. The main analytical models that determine the features of the formation of the technological phantom and the need to combine the technological phantom with the mass of the object, which provides opportunities to take into account the problems of manufacturing surface elements, determine the features of shaping the accuracy of reproduction of objects From the analytical models obtained in our work, we have the opportunity to say that for any object the technological phantom has a geometric construction, and the shape of this construction is the main factor influencing the accuracy of object formation. The research substantiates the analytical model of transformations of the technological phantom of the object, which determines the dependence of the geometric characteristics of the formation of the precision object, which is made using certain additive or destructive (with decreasing mass of the real object) technological processes. In further research, the model of shaping technological objects in space requires modeling of the peculiarities of mass representation in view of the energy connections of the technological phantom of the object in a certain volume, which has the task of determining and improving manufacturing accuracy.