Kinematic Diagram Research Articles

Design procedure of reach stacker control system

Reach stackers are efficient and maneuverable machinery for an overload of overall containers in cargo terminals and ports today. Such machinery design determines the practical interest of the engineering industry specialists. However, the lack of information in open sources about structural or kinematic diagrams of equipment control mechanisms and recommendations for their calculation does not allow an effective approach to the creation and update of reach stackers. We developed the design procedure of the reach stacker control system, which considers the kinematic and geometric parameters of the container spreader, as a result of the conducted research. It can be used in the design stages of mechanisms for spreader lateral displacement, extension of the spreader sections, spreader inclination in the vertical plane, container fixation by spreader, spreader rotation, lifting-lowering and telescoping of the boom, as well as during the real operation modes of reach stackers in cargo terminals and ports.

Development of the manipulator hinge based on the original planetary differential gearbox

For manipulation in small spaces, a compact hinge based on an original planetary differential gearbox is pro-posed. The kinematic diagram of the gearbox is described, the methodology for choosing its optimal parameters is outlined, and compared with wave and traditional planetary gearboxes from leading companies. A joint design is presented, including a planetary differential gearbox, motor, an angle sensor and slip rings. A manipulator built on the basis of the proposed hinges is described.

ДИНАМІЧНА МОДЕЛЬ ІТЕРАЦІЙНОГО ЕЛЕКТРОПРИВОДА ПОДАЧІ З ДВОМА ГВИНТОВИМИ ПЕРЕДАЧАМИ ДЛЯ ПРЕЦИЗІЙНИХ ВЕРСТАТІВ ТА ОБРОБНИХ ЦЕНТРІВ

A variant of a simplified design diagram is proposed and the corresponding kinematic diagram of a two-motor gearless drive mechanism with two screw gears (SG) is given for an iterative two-channel electric drive for the longitudinal feed of the working tool (worktable with a product) of a coordinate multi-purpose metal-cutting machine of especially high precision, model 24K70AF4. Compensators of the negative dynamic interaction of load control channels have been determined. A generalized dynamic model of the cutting process has been constructed, taking into account both the inertia of the cutting process and the influence of the machine “WT-cutter” elastic system dynamics. A dynamic model of a conditional compensator for the cutting process is determined and calculated. A refined mathematical model of motion in steady-state feed modes of the two-channel electric drive has been obtained, taking into account the compensation of the dynamic interaction of the channels on the load and the influence of friction nonlinearities in the drive mechanism and the working tool of the machine. A structural-algorithmic diagram of an iterative two-channel compensated feed electric drive with two SGs and subordinated adjustment of control channels has been designed. The diagram includes a generalized dynamic model of the cutting process and a dynamic model of the corresponding conditional compensator for the cutting process, and also takes into account the main static moments of resistance and nonlinearity of friction in the drive load. References 13, tables 2, figures 5.

Research on synthesis method of weakly coupled three-translation parallel mechanism with large bearing capacity

Aiming at the problem of poor bearing capacity in the direction of decoupled DOF of weakly coupled three-translation parallel mechanism, a class of new configurations of large load-bearing capacity weakly coupled three-translation parallel mechanisms with closed-loop unit has been proposed in this paper. Based on the screw theory, configuration evolution method, and graphical approach method, the synthesis method of these kinds of mechanisms has been proposed, and the decoupled criterion of this mechanism and the addition conditions of the kinematic pair diagram are given. The synthesis process has been developed to synthesize the single degree of freedom translational decoupled branch chain and 2T coupled branch chain. To better apply the weakly coupled mechanism to large load occasions, a closed-loop unit construction method has been proposed. Based on the theory of singular value decomposition, a theoretical formula for increasing the load-bearing capacity of a mechanism by constructing a closed-loop unit with redundant drives has been derived for the first time. The closed-loop unit is added to the 2T coupled branch chain and the single DOF decoupled branch chain to construct the large load-bearing capacity single DOF decoupled three-translation parallel mechanism. Kinematic analysis and static analysis have been carried out on the synthesized mechanism. The Jacobian matrix of the synthesized mechanism is a block diagonal matrix, and the bearing capacity is significantly stronger than that of the decoupled mechanism, even higher than that of the coupled parallel mechanism. The synthesized weak coupling three translation parallel mechanism with large load bearing characteristics has a good application prospect in the field of high precision and large load bearing.

REDUCING THE KINEMATIC ERROR OF AN ECCENTRIC TRANSMISSION
 WITH A PARALLEL LOCATION OF INPUT AND OUTPUT SHAFT
 AS A RESULT OF THE APPLICATION OF A DOUBLE-FLOW LOADING SCHEME

The article presents kinematic diagrams and computer analysis of three types of eccentric transmission schemes.
 The graphical dependences of the kinematic error of the eccentric transmission are presented for the coaxial and
 parallel arrangement of the input and output shafts in two single-flow loading schemes. Computer analysis of an
 eccentric transmission with single-flow loading schemes showed that the kinematic error with the coaxial arrangement
 of the input and output shafts is 30 times lower than with the parallel arrangement of these shafts. In order to reduce
 the kinematic error of an eccentric transmission with a parallel arrangement of input and output shafts, a two-flow
 loading scheme was proposed. It has been established that the use of a double-flow loading scheme makes it possible
 to reduce the kinematic error by 12 times compared to a single-flow loading scheme with a load on the output shaft
 of 10 N∙m.
 It is planned to use the design of an eccentric transmission with a parallel arrangement of input and output
 shafts with several power flows when designing various types of gearboxes for cultivators.

Multivariate analysis of the kinematics of an upper limb rehabilitation robot.

Purpose: The purpose of this work is to present a multivariate analysis of the kinematics of an upper limb rehabilitation robot. Comparing multiple concepts of kinematic chains makes it possible to identify advantages and disadvantages and, as a consequence, choosing the optimal solution to create a physical device. Such actions shall contribute towards automation of the rehabilitation process, bringing benefits to both therapists and patients in comparison with conventional rehabilitation. Methods: Multivariate analysis of kinematics was performed on the basis of three concepts of the kinematic chain of an exoskeleton, enabling the rehabilitation of both right and left upper limb within the area of the shoulder joint, elbow joint and wrist. The kinematic chain allows the performance of simple and complex movements. Results: The results of the conducted multivariate kinematic analysis define specific movements and angular ranges, which may be performed while applying one of the proposed concepts of the robot design. The results made it possible to determine the optimum solution to the kinematic diagram and construction design, which best satisfy the expectations for effective rehabilitation. Conclusions: The analysis of the kinematic diagram concept of the exoskeleton should be done in relation to its design (construction form). Considering the obtained parameters, it is necessary to find an optimum concept and wisely manoeuvre the values, in order to avoid a situation in which one significant parameter influences another, equally important one. It is noteworthy that the introduction of changes into particular segments of the kinematic chain often has a significant impact on other segments.

Development of technical solutions for modernization of the rotary feed mechanism of a quarry drilling rig

This article substantiates and describes the design and operating principle of an electrohydromechanical rotator, presents the results of experimental studies of a prototype, shows ways to reduce dynamic loads and recommendations for improving the rotary-feeding mechanism of a drilling rig of the SBSh-250MNA-32 type. An improved kinematic and hydraulic diagram of an electrohydromechanical rotary-feeding mechanism and installation of a feed pump with a drive electric motor in the machine room of a drilling rig are presented. A design has also been developed for the electrohydromechanical rotary-feeding mechanism of the drilling rig, which can significantly reduce transmission vibrations, increase durability, and, as a result, the productivity of the machine.

Controlled power distribution mechanisms in the transmission of an integral tractor

The key features of the integral tractor concept are considered. The roles of controlled inter-axle and inter-wheel power distribution mechanisms are analyzed. Variants of the transmission structure are proposed. An example of simplified kinematic diagrams of interaxle and interwheel power distribution mechanisms is considered. Approaches to determining the external parameters of such mechanisms, their control technology, and the technological base for their design and manufacture are proposed.

STUDY OF THE KINEMATICS OF THE POSITIONING MECHANISMS OF WIDE-GRIP MACHINE-TRACTOR UNITS

As stated in the humanitarian food program "Grain from Ukraine", launched by the President of Ukraine Volodymyr Zelenskyi: "The demand for agricultural products in the world is growing by 2-3% every year, and the shortage of grain on the markets of Africa and Asia may reach 10-15% already in 2024". Therefore, the issue of production of agricultural products is relevant today. As the analysis of the market of agricultural machinery shows, one of the directions of the development of the design of agricultural units is to increase the width of grip of tools for soil cultivation and plant care. The use of agricultural units with an increased working width has certain advantages: - reduction of the number of passes of equipment on the ground; - reduction of fuel consumption; - reducing the negative impact of the unit on soil density. Among the disadvantages of this type of aggregates should be attributed the increase in turning radii, as a result of the increase in width. It is possible to eliminate this shortcoming by quickly transferring the unit from the working position to the transport position and vice versa. To fulfill this task, a review of known designs of wide-grip aggregates was carried out. Known hydraulic drives for raising and lowering and folding and unfolding sections are considered. A kinematic diagram of the mechanism of rotation of the extreme section of the cultivator relative to the frame has been developed. Based on this calculation scheme, the reactions in the hinges were determined and the graphical dependencies of the mutual location of individual elements with respect to the angle of rotation φ were calculated. The existing hydraulic positioning mechanisms, which are equipped with chainless wide-grip machines and tools with articulated frames, do not provide the necessary maneuvering properties of MTA during their movement on the turning lane. Equipping hydroficated positioning mechanisms with follower stabilizing devices is a promising direction for improving hydraulic drives of machine-tractor units, which create prerequisites for reducing the turnaround time on the turning lane by selecting the parameters of the specified equipment. The most important factor affecting the stability of the positioning of the sections of wide-grip machine-tractor units is the variable load that occurs on the hydraulic cylinder rod at the moment of turning the sections around the horizontal hinges at an angle of more than 90⸰, which causes inconsistency in the flows of the working fluid entering and leaving the hydraulic cylinder , which leads to the interruption of the flow in the cavity of the hydraulic cylinder, which is connected to the injection hydraulic line.

Evaluation of the operating conditions of the Stirling engine heat exchangers

The development of modern energy is inextricably linked with the further improvement of heat engines, which are still the only primary sources of mechanical energy on an industrial scale. Given the existing environmental problems, Stirling engines can be a good alternative to internal combustion engines and turbines. Of the many problems of creating such a sufficiently powerful and economical engine, it is customary to consider three main ones: 1) efficient transfer of large heat fluxes in the heater, regenerator and refrigerator; 2) creation of reliable and durable seals to hold the working fluid in the cylinder; 3) ensuring minimal friction in bearings and seals. And yet, of the three listed problems, the first should be given more attention, first of all, due to the unique conditions associated with the continuously changing thermo and mechanical loads. The instability of the loads is further complicated by the sharply different heat transfer coefficient on the external and internal heat transfer surfaces. That is, there are factors that contradict the requirements for the size of the heat transfer surface, the friction resistance of the working medium and the dead volume of the engine as a whole. In this regard, it is of interest to search for possible ways to reduce the effect of negative factors of non-stationary heat transfer in the calculation of heat exchangers. The current lack of suitable theoretical methods of calculation forces the use of semi-empirical methods. The aim of the paper is to assess the significance of the unique, characteristic of Stirling engines, the negative phenomenon of the delay in the flow of the working fluid in heat exchangers. For this purpose, a real kinematic diagram of the movement of the engine pistons with a rhombic drive by R. Meyer, created using the design program, is used. The analogue is the 4–235 type real engine of the Philips Company. In the calculations, a step-by-step procedure for calculating the time-varying parameters of the working fluid is used. The need for such a solution is due to the fact that in the rhombic drive of R. Meyer, the pistons movement and the change in the displaced volumes complexly depend on the angle of rotation of the engine shaft. In addition, the exact value of the real change in volume is possible only when the terms of the analytic equation of volume change under consideration are decomposed into a Fourier series.

Дослідження нелінійних горизонтальних коливань слабозакріпленого вантажу при русі автомобіля

The improvement of the methods of reducing dynamic loads in the elements of self-propelled transport machines and transported goods is based on the results of the analysis of dynamic phenomena that occur during their operation, which is due to the growth of load, increase of working speeds, combination of loading and unloading operations with other technological operations, increase in productivity.
 To prevent damage and ensure traffic safety, packaging and artificial cargoes are secured in car bodies, train carriages and ship holds with wire ties, thrust and spacer bars, tying and other methods.
 But during transportation, as a result of stretching and breaking of stretch marks and pulling out of nails, goods are damaged, moving in a body, wagon or hold. Therefore, it is very important at the design stage of the fastening structure to establish the possible movement of the load, as well as to ensure it within the given limits in order to prevent damage to the load.
 The authors proposed a method of calculating load fluctuations in the body of a truck using the example of two loads of different weights. A kinematic diagram of a self-propelled transport machine with sequential elastic coupling of transported loads was built and a study of nonlinear horizontal oscillations of a loosely secured load during the movement of the vehicle was carried out.
 According to the results of the research, graphs of the dependences of the dimensionless amplitude of the weight of the load relative to other loads depending on the gap between the fasteners were constructed. Maps of regions of stable movements are constructed and the region of unstable movements of loads is shown. It is noted that although such an area of unstable movements is quite small, but under certain conditions of movement of the vehicle and weakly secured cargo, phenomena can occur that can cause a traffic accident.

Development of a spatial orientation model for the actuator of a mechatronic system

Purpose. Development of a control system for a mechatronic system, taking into account the geometric solution of the inverse kinematics problem. The methods. The research was based on the principles of theoretical and applied mechanics, as well as the Denavit-Hartenberg transformation model. The formation of graphical computational models and kinematic diagrams simplified the development of the mathematical model of the dynamic system without considering the forces acting on the mechanism links. The possibility of using matrix transformations to simplify the search for generalized coordinates and transition to the local disposition of each link was explored for further integration of the obtained results into automation and control systems. Findings. The obtained results, determining the trajectory of the gripper using inverse kinematics models, allowed the development of algorithms for determining the position of mechanism links with the possibility of software implementation of the control system. Identifying patterns for determining accurate position coordinates by the matrix method allows the application of open-source software for real-time position calculations. The originality. The use of modern technologies for visual assessment of the external environment and coordinating control impulses of the executive body drive was first achieved based on the mathematical model of the inverse kinematics of a multi-link mechanism. This automated the determination of local coordinates for each link within its degrees of freedom and algorithmized this process. Combining the mathematical models of mechanism kinematics and the matrix form of coordinate search allows investigating the influence of the displacement of the i-th link of the mechatronic technical complex on the overall system, considering the acting force systems and the specified spatial orientation of both the executive body and intermediate links. Practical implementation. The implementation of obtained kinematic models using the matrix method enables the software realization of algorithms for searching the coordinates of the i-th mechanism link, automating the control process with the task of final positions, determining the level of integral error during the displacement of the initial link, and providing the possibility of programming autonomous mechatronic systems with open-source code. As a result, the introduction of semi or fully autonomous technical complexes will automate technological processes in various industries.

Теоретическая оценка коэффициента полезного действия сферической шариковой передачи, работающей в мультипликаторном режиме

The paper considers issues of creating multipliers for the medium power wind generators. It proposes a basic kinematic diagram of the multiplier mechanism based on the spherical ball gear. The satellite makes a spherical motion during the gear operation, and the intermediate rolling elements mounted on the satellite in two rows are moving along the drive shaft and the housing sleeve treads. The gear under study makes it possible to realize large values of the gear ratios and speed multiplication factors with small overall dimensions and weight, respectively. An algorithm was developed for theoretical determination of the gear average efficiency in the reducer and multiplier modes depending on its geometric parameters and friction coefficients. The paper studies influence of the multiplier coefficient transfer, difference in the number of balls in the satellite rows and friction coefficient on the efficiency. Computer simulation results of the gear operation were received in the NX system, which confirmed the obtained theoretical dependencies.

Electromechanical transmission for active release trailer

The issues of the features of the use of active trailers as part of road trains of forest machines are considered. The principles of constructing a block diagram, determining external parameters and synthesizing kinematic diagrams of the mechanical part of the electromechanical transmission of an active trailer are proposed. A variant of the kinematic scheme of the power distribution mechanism is given. A technology for controlling such mechanisms is proposed. The ways of project realization are shown.

Digital twin in the system of external adaptive control of robot manipulators

The article discusses the implementation of a digital twin in the system of adaptive control of robotic manipulators. The use of digital twins to plan, control and maintain the life cycle of production equipment forms the sustainable introduction of robotic systems into the technological processes of high-tech enterprises. The use of a digital twin in the collaboration of a robot system allows you to design more versatile workplaces and assembly lines, and optimize their workload. A new approach is proposed that allows solving problems of direct and inverse kinematics for robotic manipulators. The approach is to represent the kinematic diagram of a robotic arm with six rotational joints as a vector model. Due to the low computational load, the use of the proposed approach in control systems makes it possible to reduce delays when working in real time, with the ability to increase the number of robotic arms and control with higher accuracy.

Synthesis of Four-Bar Linkages by Four Infinitely Close Relative Positions and Pressure Angle

A computer-applicable linear mathematical model has been developed to determine Burmester’s curves for infinitely close relative positions (cubic of stationary curvature), which indirectly uses Carter-Hall’s circle. By varying a free parameter and using elements of kinematic and analytical geometry, an incomparably simpler solution is achieved than that obtained by the third-degree equations of the Burmester's curves for stationary curvature. The mathematical model for the synthesis of four-bar linkages includes and a condition for the pressure angle, whereupon is uniquely defined the kinematic diagram of the mechanism. Of the pressure angle, the reactions of the forces in the kinematic pairs and the force sizing of the mechanism depend. The model would facilitate the engineers in the synthesis of four-bar linkages by generating a function approximating a given function in the vicinity of a given position, where the two functions have four infinitely close common points (3rd-order approximation). An example of the synthesis of a four-bar linkage illustrates the application of the model, which is linear - it includes only equations of straight lines written in Cartesian coordinates, which is why it is convenient for computer calculations.

Wyznaczanie parametrów kinematycznych agregatu sprężarkowego w zastosowaniach z LPG

The collection and transportation of low-pressure gas released into the atmosphere from the oil fields is important in increasing gas production. This issue, which differs in its actuality, has both economic and pollution preveniton benefits. One such project, led by the UN Development Fund, was successfully implemented in the city of Siyazan, Azerbaijan. An electrically driven compressor unit of NQK-7/1-5 type with two oscillating cylinders is commonly used for such work. On visual inspection of the compressors undergoing repair, it was found that the seals in the pneumatic part and the elements of the cylinder-piston group are completely out of order, the gear teeth in the transmission part are broken, worn, the bearings are destroyed, the belts are torn, etc. Compressors sent for repair are almost always reassembled. A structural-kinematic analysis of the compressor installation was carried out to find out the causes of the existing malfunctions. For this purpose, a kinematic diagram of the conversion mechanism of the compressor – a slider-crank linkage mechanism was drawn up using the method of closed contours from projection equations relative to the X and Y axes, and based on the condition that the rotation angles of the piston and cylinder axes are equal, the instantaneous rotation angle, angular velocity and angular acceleration of the cylinder rotation, as well as instantaneous values of displacement, speed and acceleration of the piston inside the cylinder were found. It was shown that the designer's decision on the selection of the design scheme and determination of the product dimensions, which are one of the main issues in the design of the mechanism, should be made based on the results of the kinematic and dynamic analysis.

A study of electrothermomechanical converter for technological purposes with nonlinear changes in the loading and cooling medium

Heavy temperature processes with high-temperature loads require optimisation of technological processes, ensuring high reliability and combining rotating parts of electric machines with actuators to achieve greater efficiency of electromechanical converters. The research aims to provide a theoretical justification and experimental confirmation of the effect of higher harmonics in the air gap under nonlinear changes in the temperature of the medium. The research is based on the basic principles of electrodynamics, heat and mass transfer, mathematical modelling by the finite element method, and experimental verification of multi-physical parameters. Based on the analysis of the differential equation for determining the increase in the surface temperature of a ferromagnetic rotor under conditions of nonlinear temperature changes in the environment surrounding the electromechanical converter, the regularities of the formation of the free and forced components of the instantaneous temperature values of the massive rotor are established. Depending on the mode of interaction between the load-cooling medium and the electromechanical part of the screw units, kinematic diagrams of single-mass and two-mass systems with variable or constant moments of inertia and stiffness were formed. According to the size of the electromagnetic system of the experimental sample, a mathematical model for studying thermal and electromagnetic processes was built. The regularities of the spatial distribution of the temperature of the screw electromechanical unit are determined. The spectra of higher harmonics of voltage and current in the frequency range from 0 to 50 kHz have been experimentally determined, which confirms the presence of the effect of generating higher harmonics when the temperature of the medium surrounding the rotor screw changes. The detected harmonic spectrum affects both the formation of the dynamics of the rotating system and additional thermal power while increasing the overall efficiency of the screw electromechanical converter. The practical value of the obtained results lies in the possibility of predicting the optimal indicators of interrelated electromagnetic and heat exchange processes in screw electromechanical converters for technological purposes

The double-flow electromechanical transmission of tracked vehicle

BACKGROUND: Specific demands to ensure high mobility and low energy consumption while cornering are given in the process of development transport and special tracked vehicles. Therefore, improvement of values of these parameters is a relevant objective. The mentioned parameters are directly dependent on the chosen type of transmission.
 AIM: Derivation of transmission kinematic schemes that provide the best opportunities to ensure the quality of tracked vehicle cornering control with relative simplicity of design.
 METHODS: Derivation of transmission kinematic schemes and analytical evaluation of expected transmission properties were based on fundamentals of the theory of ground vehicle dynamics.
 RESULTS: The kinematic diagram of a double-flow transmission and rotation mechanism for a transport vehicle with two engines is proposed. The proposed scheme is applicable for tracked chassis, wheeled vehicles using the skid-steering method. The proposed principle of transmission construction can be adapted for a ship with a hybrid powerplant. The modes of operation of the proposed mechanism are presented, its main kinematic and power features are given. An assessment of the required power of the traction electric motor as part of a hybrid powertrain of a transport tracked vehicle weighing 4550 tons was carried out. Special attention is paid to the problem of the possibility of manufacturing a hybrid powertrain with the proposed transmission based on components, the production of which has been produced in the Russian Federation.
 CONCLUSIONS: The proposed transmission scheme may be used for development of new machinery as well as for upgrading of existing vehicles. Main advantages of the proposed scheme are simplicity, compactness, and engine functions duplications. Specific advantages for a transport vehicle with an regenerative steering system are ensuring the mechanical energy recuperation during cornering and braking and ensuring turning the production of a pivot turn.

СКЛАДАННЯ МАТЕМАТИЧНОЇ МОДЕЛІ ВІБРАЦІЙНОГО СТОЛУ

In this article, a mathematical model is obtained, which combines the design and technological parameters of the technological set of equipment for the concrete goods production (vibrating table), in which the vibrating exciter is fixed on the lever vertically in the center under the plate compactor. This equipment is used for the manufacture of small-sized concrete products. The mathematical model is composedwith the help of Lagrange equations of the second kind, which are the most common method for solving problems about the motion of a mechanical system. Methods of mathematical physics and physical and mathematical modeling by methods of applied mechanics were used in the compilation.To determine the position and describe the free motions of the material bodies that make up the mechanical system under consideration, an orthogonal vi-brational reference system of three coordinate systems was used. Analyzing the kinematic diagram of the vibration table, it is determined that the position in space of all material bodies of the mechanical system, which simulates the specified vibrating table, can be uniquely set by the following independent parameters: Cartesian coordinates, vibration angles and the angle of rotation of debalance.Thus, the mechanical system in question has seven degrees of freedom with seven generalized coordi-nates.As a result, a mathematical model of a vibrating table for concrete products manufacturing in the form of seven second order differential equations system, which describes the vibrating table spatial motion surface, is obtained.The theoretical values of the vibrating table vibrations amplitude at variable lever length were also determined and compared with experi-mental data at the same initial parameters. The difference was 15%, which confirms the adequacy of the created mathematical model to the real technological process on the vibrating table, which is being studied.Analyzing the change in the vibration oscillations amplitude on the vibrating table working surface from the change in the lever length on which the vibrating exciter is fixed, it was found that the lever fixation allows an almost linear increase in the amplitude of vibration oscillations due to an increase in the lever length. This, in turn, makes it possible to reduce energy consumption when compacting the concrete mixture.