Kinematic Scheme Research Articles

Modeling the management of a service underwater vehicle while maneuvering in an environment with obstacles

Difficulty in the development of the Arctic and the Far North are associated not only with the harsh natural conditions, but also with extreme professional risk. High-risk underwater operations at industrial facilities requires for underwater robots. Many works (inspection, docking with manifolds, etc.) are associated with operations in an environment with obstacles. The use of robotic systems is a natural choice in these conditions, especially at offshore facilities. The most difficult and dangerous are underwater operations on offshore production platforms and transporting offshore pipelines. For high-risk underwater operations at industrial facilities, service autonomous underwater vehicles (PA) are required. Many works (inspection, operations on manifolds docked with collectors, etc.) are associated with operations in an environment with obstacles; therefore the kinematic scheme of the underwater vehicle should provide increased maneuverability and ease of use when working in an environment with obstacles. When developing the appropriate control mode for the underwater vehicle (UV), it is important to consider the dynamic parameters of the UV when solving the problem of its positioning (the positioning problem itself can be solved by means of a technical vision system - TVS). The article discusses two generalized models of UV for work on man-made objects and the results of computational experiments that simulate the reduction of UV to a target point, the coordinates of which are determined using the TVS.

3D modelling of angular spindle’s head for machining centre

The unified design of the angular spindle head of the machining centre for drilling-milling and boring type is considered. Three-dimensional modeling of the angular head assembly in CAD KOMPAS-3D is performed using a specialized application “Shafts and 3D mechanical transmissions” including a three-dimensional representation of the machining centre kinematic scheme. The photorealistic visualization module Artisan Rendering, which is integrated into the KOMPAS-3D CAD contour, was used to create presentations and promote this construction to the machine tool industry. A two-stage procedure for analyzing the structure by the stiffness criterion is proposed: at the early stages of the design by the matrix initial parameters method; at the stage of the working project by the finite element method in the APM FEM module. The procedure for determining the stress-strain state of the angular head spindle with end mills realized.

Characterization of uses of trigonometric notions in Mechatronics Engineering from Mathematics Education

From the Socioepistemological Theory we propose that even with the curricular articulation presented in school programs of Engineering it exists a disarticulation of uses of mathematical knowledge, this is displayed more emphatically when a student takes professionalizing courses. We proposed the research question of: what uses of trigonometric notions are given in Mechatronics Engineering when students solve problems in Robotics? we use the Socioepistemological Theory in tandem with the ethnographic method to identify and characterize them in their cultural framework. By the delimitation of the study to a community of Mechatronics Engineering in a Mexican university and the direct kinematics problem in the subject of Industrial Robotics, we characterize that trigonometric notions are given an arithmetic, metric, quantitative and algebraic usage, and by them, the Trigonometry acquires more significates aided by the construction of visual references that allow the mathematical modelling that was done, and from which we recognize in the pseudo-concrete models (drawing and kinematic schemes) the reason to be for Trigonometry as a tool for Robotics: the determination of the position in a circle or circular sector.

Choice of energy accumulator parameters for a new peripheral docking mechanism

Spacecraft docking is a controlled on-orbit mechanical assembly process realized using active and passive docking units. The docking mechanism of the active unit provides capture conditions, attenuation of active spacecraft approach energy, alignment and retraction of the docking units before their hard connection. A kinematical scheme of a new peripheral docking mechanism is considered in this paper. Instead of energy damping, it is based on energy accumulation using springs with controlled recoil blocking. The blocking is activated before docking and keeps the docking mechanism in its initial position. On the first contact signal, the blocking is switched off releasing the energy of compressed springs for quick forward moving of the docking ring and improving capture. The blocking is activated again after capture and approach energy is accumulated by the springs without returning to the mechanical system. Avoiding contacts of docking mechanism links between each other and with the docking unit body is important for peripheral mechanisms due to their design. A procedure for choosing parameters of an energy accumulator that allows attenuating a max permissible energy without link contacts and without exceeding the max permissible value of the axial interface load is considered here. Key words: spacecraft, docking, docking mechanism.

A novel inverse kinematics scheme for the design and fabrication of a five degree of freedom arm robot

In this paper, analysis and fabrication of a laboratory model of a five degree of freedom arm robot for pickup and drop applications along with the governing kinematics is investigated. SolidWorks and SimMechanics were applied as the design-fabrication and motion analysis softwares, respectively. To reduce the weight and power consumption and improve the manufacturing time, plexiglas was used as the fabrication material. A novel geometric approach for the inverse kinematics is proposed and as a consequence the addition of the orientation of the specimen along with the location of the end effector as the inputs of the inverse kinematics problem, resulted in the improved workspace and minimum computational error, which enhanced the robot efficiency. The proposed novel inverse kinematics scheme is based on the formulation of the end effector position in terms of the global coordinates and the geometry of the robot; and accordingly determining the join angles in terms of the governing parameters and the desired end effector position. The proposed method led to a considerable reduction of positioning error. In order to validate the simulation outputs, the corresponding results are compared to those of the laboratory model.

THE TECHNOLOGY OF CO-CULTURING OF POTATOES WITH HONEY PLANTS AND PROSPECTS OF ITS TECHNICAL SUPPORT

The right way out of the crisis of the agro-based industries is the maximum use of the opportunities of scientific and technological progress and the orientation of the real economy to innovative development. One of the promising technologies of crop production is an innovative technology in potato growing, which provides for the co-culturing of potatoes with honey crops. Phacelia tanacetifolia (PhaceliatanacetifoliaBenth) is selected as honey crop, which is a valuable green manure. It allows to reduce the need for organic and mineral fertilizers, increases the ecological cleanness of products, favors the growth of potato yield, provides the additional honey yield. Phacelia significantly improves the soil structure, displacing a significant part of weeds, providing natural loosening of the soil, protection from drying out, from pests and parasites. The co-culturing of potatoes with phacelia protects the environment from the use of dangerous plant protection products. If the economic effect is defined as the difference between the profits of innovative and traditional technologies, then, according to preliminary calculations, the level of profitability of innovative technology in potato growing is 1.9 times higher, and the profit from 1 ha is 1.6 times higher compared with the traditional technology. Large-scale development of the proposed technology is hampered by the lack of potato planters and seed planters, which provide planting of potatoes and sowing seeds of honey crops simultaneously, in the Russian market and the markets of the European Union. An innovative technology - mounted seeder for potato planters was developed by the staff members of the Pskov State University. The article describes the main agro-technological requirements to this device. A general model and a kinematic scheme were developed to visualize the combination of the working elements of the potato planter and the mounted seeder. The developed model falls into the type of seed planters, which is designed to sowing in drills the seeds of honey crops (phacelia) in the furrow between potatoes at the time of the forthcoming closing of this furrow by soil, and can be used in agricultural engineering. Potential consumers of the proposed innovative technology in potato growing and the developed mounted seeder are farm enterprises and agricultural production cooperatives, which have small plots of land, use crop rotation systems in potato growing, and work for reducing costs and increasing the yield of potato cultivation.

KINEMATICS OF METALLURGICAL CUTTERS WITH PARALLEL BLADES

Cutting with parallel blades cutters consists of three periods: blades ridging in metal; cutting; chipping (separation). Maximum force is required at the end of the ridging period and at the beginning of cutting. Since one of the blades is stationary, the second blade in cutting process has to go deep into the entire thickness of metal to cut the billet. For example, if thickness of metal is20 mm, then the upper blade needs to pass20 mmfor its cutting. If you make both blades moving towards each other, cutting effort will be less. In this case, each blade cutting20 mmof metal will pass 10mm. In order not to make mechanism of cutter with two movable blades too complicated, it is important to ensure its mobility from one drive. So, there acute the issue of arrangement possibility of blades moving towards each other with guaranteed strength of the units, transmitting effort on the blades. Kinematic scheme of cutters with blades moving parallel to each other in a vertical plane is proposed. Advantages of the proposed cutters design are the following: counter movement of blades requires less effort to cut the billet; force from each blade is distributed to two connecting rods, reducing load on each of them; since blades move towards each other, the main cutting force is distributed along the units of the mechanism and is transmitted to the engine, which reduces load on the frame and foundation when cutting; when blades move towards each other, metal separation occurs faster, it allows to concentrate maximal force during cutting with minimal load on the engine; the cut part of the billet does not fall below the roller bed at the end of cutting, so installation of the lower movable table is not required. Mobility of the proposed mechanism is determined by P.L. Chebyshev formula with its value = 1. Kinematic analysis of blades is carried out using a special method, which is in using point of connecting rods intersection.

Four-wheel steering and driving mechanism for a reconfigurable floor cleaning robot

Abstract The fixed morphology cleaning robots lack adaptation to the unstructured environment to access and perform cleaning. Reconfigurable robots such as hTetro developed in our previous work have solved this problem, however the issues of robot's locomotion maneuverability and the associated real time control have not been resolved. This paper is aimed to validate whether a four wheel independently-controlled steering and driving (4WISD) mechanism can provide an effective solution for high maneuverability of the robot and can serve as a single mechanism for locomotion and transformation with a control strategy. After an extensive review of the existing reconfigurable robots including the hTetro platforms developed in our previous work and locomotion modules of mobile robots, the current hTetro platform with 4WISD mechanism is proposed. After it is designed and fabricated, experiments are conducted to verify its effectiveness. Experimental results show that the proposed 4WISD and the open loop kinematic control scheme deliver the high maneuverability of hTetro platform when following a circular path in various locomotion modes. The experimental results show the proposed 4WISD mechanism and kinematic controller make the hTetro platform achieve the desired maneuverability. In addition, the future work to improve the locking among the sub-modules of the robot and to further reduce the path deviation error of kinematic control is identified. Based on the work reported in this paper, the locking mechanism among the sub-modules of hTetro platform will be improved and the closed loop kinematic and dynamic control schemes will be developed to make it perform cleaning tasks in uncertain environments.

Momentum-space threshold resummation in tW production at the LHC

We calculate the soft-gluon corrections for tW production to all orders. The soft limit is defined in the pair invariant mass or one particle inclusive kinematic schemes. We find that at NLO the contribution of the soft-gluon effect dominates in the total cross section or the differential distributions. After resumming the soft-gluon effect to all orders using the renormalization group equation, we find that the NLO+NNLL results increase the NLO cross sections by 12% ∼ 17% depending on the scheme and the collider energy. Our results are in agreement with the measurements at the 8 and 13 TeV LHC. We also provide predictions for the total cross section at the 14 TeV LHC.

A lightweight interpolation algorithm for short-segmented machining tool paths to realize vibration avoidance, high accuracy, and short machining time

A computationally efficient FIR-filtering based path-smoothing algorithm which simultaneously realizes vibration avoidance, high accuracy, and short machining time is proposed in this paper. Unlike the case of long G-line blocks where only the adjacent blocks affect the cornering error of a specific corner, more than two blocks affect the error in the case of short-segmented blocks. To satisfy the tolerance error, point-to-point (P2P) technique can be applied, but its machining time will be excessively elongated due to full stops at each corner. Alternatively, motions with the delay times of FIR filters fully-overlapped, which are available on commercially-installed NC systems, can realize short machining time, but they cannot satisfy the tolerance error due to the filtered trajectories accompanies by high speed. Other methods such as spline fitting may satisfy the tolerance error and realize short machining time, but they will allow vibration of the machine tool structure since these motions are not allowed to be filtered for satisfaction of the tolerance. Therefore, no method exists which realizes vibration avoidance, high accuracy, and short machining time all at the same time. For the first time in the literature, a method is proposed which realizes all of the above requirements. The proposed algorithm bases on a kinematic smoothing scheme where no spline-fitting based geometric smoothing is required, and the blended path geometry is only controlled by optimizing the feedrate (speed) profiles along a span of short G01 and G02/G03 moves. FIR filtering is applied to avoid the inertial excitation of the machine tool structure, and a novel “block splitting” method is proposed to keep elongation time of the G-line blocks the minimum. The effectiveness of the proposed method is validated through a series of experiments by comparison with conventional methods.

Novel solutions for actuation of an above elbow prosthesis

The above elbow prosthesis must provide the movement of the elbow, which naturally is composed by a flexion – extension movement. The mechanical system must fulfil a set of conditions regarding kinematics, dynamics, precision, size and load. The paper describes two novel solutions to generate the flexion – extension movement of the elbow. The description contains the kinematic scheme, elements of calculus and the CAD generated constructive solution.

Kinematics and arrangement of an active sidestick

The article is about design of the active aircraft control sidestick. The disadvantage of the known frame constructions, apart from the large dimensions, is the difference in the dynamic characteristics of the channels when using the same actuators, because the mass of a frame mounted actuator is the load for a fixed base mounted actuator. As a result the kinematic scheme of an active control sidestick which don’t use a frame is offered. The frameless scheme contains two identical actuators mounted on the fixed base, at that the interference of channels is excluded. The derivation of the actuator’s gear ratio is given. It is shown that this dependence between the rotation angle of the actuator output shaft and the handgrip deflection angle is of a sinusoidal type and that it is close to linear in the range of the handgrip operating angle.

ОСОБЕННОСТИ МОДЕЛИРОВАНИЯ КОНИЧЕСКОЙ ПЕРЕДАЧИ ДЛЯ СМЕСИТЕЛЯ С ДВУНАПРАВЛЕННЫМ ВРАЩАТЕЛЬНЫМ ВОЗДЕЙСТВИЕМ НА МАТЕРИАЛ

A batch mixer is considered. The feasibility of developing a new type of mixers is presented. A literary review of domestic and foreign authors on this subject is made. The author's kinematic scheme of the mixer is presented. It describes the effect on the material mixed in the mixing chamber with respect to two mutually perpendicular horizontal axes. Movement features of material in the mixer suggest the presence of elements of the gyroscopic effect. Rotation of the mixing chamber is carried out by means of belt, chain and conical transmission. The resulting complex spatial motion of the material particles can be controlled by a frequency converter and the selection of appropriate gears. An algorithm for modeling the conical transmission for a mixer with a bi-directional rotational effect on the material is presented. Bevel gear is set on the carrier. Preliminary experimental studies have been conducted. A three-dimensional model of the bevel gear is presented. Adjustment of the installation dimensions is shown. A three-dimensional model of a bevel gear transmission, using the NX software product, is supplemented with a table for its calculation and an initial stocking model. The practical implementation of bevel gears in metal is shown. conclusions on modeling are made.

Something about a Railbound Forging Manipulator

Heavy payload forging manipulators are mainly characterized by large load output and large capacitive load input. The relationships between outputs and inputs have greatly influenced the control and reliability. Forging manipulators have become more prevalent in the industry today. They are used to manipulate objects to be forged. The most common forging manipulators are moving on a railway to have greater precision and stability. They have been called the rail-bound forging manipulators. In this paper, one presents the general aspects of a rail-bound forging manipulator, like geometry, structure, general kinematics and forces of the main mechanism from such manipulator. The kinematic scheme shows a typical forging manipulator, with the basic motions in operation process: Walking, the motion of the tong and buffering. The lifting mechanism consists of several parts including linkages, hydraulic drives and motion pairs. An idea of establishing the incidence relationship between output characteristics and actuator inputs is proposed. Self-forging systems have the ability to achieve an open, fast, direct forging of products that are often heavy and heavy but also bulky. Open forging productivity is generally very high, it is determined not only by the capacity of forging press but obviously dynamic handling by forging manipulator. The most prominent and qualitative forging machines are the DANGO and DIENENTHAL series, equipped with high dynamic devices and specially designed to operate on heavy forging presses. They ensure the reliability and repeatability of all forging cycles. Even a modernization of existing forging machines with D&D machines will improve the capacity and quality of these facilities. D&D handlers allow to forge nearly clean shapes and guarantee superior surface qualities, thus saving energy, improving production and saving costs during the machining of parts. Savings due to shorter process times and reduction of reheating cycles result in shorter recovery time.

Design and Kinematic Control of the Cable-Driven Hyper-Redundant Manipulator for Potential Underwater Applications

Underwater manipulators are important robotic tools in the exploration of the ocean environment. Up to now, most existing underwater manipulators are rigid and with fixed 5 or 7 degrees of freedom (DOF), which may not be very suitable for some complicated underwater scenarios (e.g., pipe networks, narrow deep cavities, etc.). The biomimetic concept of muscles and tendons is also considered as continuum manipulators, but load capacity and operation accuracy are their essential drawbacks and thus limit their practical applications. Recently, the cable-driven technique has been developed for manipulators, which can include numerous joints and hyper-redundant DOF to execute tasks with dexterity and adaptability and thus they have strong potential for these complex underwater applications. In this paper, the design of a novel cable-driven hyper-redundant manipulator (CDHRM) is introduced, which is driven by multiple cables passing through the tubular structure from the base to the end-effector, and the joint numbers can be extended and decided by the specific underwater task requirements. The kinematic analysis of the proposed CDHRM is given which includes two parts: the cable-joint kinematics and the joint-end kinematics. The geometric relationship between the cable length and the joint angles are derived via the established geometric model for the cable-joint kinematics, and the projection relationship between the joint angles and end-effector’s pose is established via the spatial coordinate transformation matrix for the joint-end kinematics. Thus, the complex mapping relationships among the cables, joints and end-effectors are clearly achieved. To implement precise control, the kinematic control scheme is developed for the CDHRM with series-parallel connections and hyper-redundancy to achieve good tracking performance. The experiment on a real CDHRM system with five joints is carried out and the results verify the accuracy of kinematics solution, and the effectiveness of the proposed control design. Particularly, three experiments are tested in the underwater environment, which verifies its good tracking performance, load carrying and grasping capacity.

3DoF Parallel robot analysis

This paper addresses a 3DoF parallel robot. A kinematic scheme and joint types are proposed. Kinematic analysis of the mechanism is done. Aspects of robot control are considered: a power supply, a controller.

Reducing of dynamic loads of excavator actuators

In the article, using the example of the walking excavator ESh 20.90, the results of studies on the choice of design parameters of the traction mechanism ensuring the reducing of dynamic loads, based on solving the inverse dynamic problem according to a given type of oscillatory movements of the actuator and using the theory of mechanical circuits are presented. By numerical simulation of the electromechanical system it is shown that the introduction of an additional elastic-damping device in the kinematic scheme of the excavator traction mechanism will allow to reduce the dynamic loads and the duration of their action on the traction mechanism in the start-up and load-step modes and significantly increase the logarithmic decrement of the elastic oscillation.

The development of methods for determining vibration stochastic fields of technological complexes

The force effects occurring in technological complexes have been studied on the basis of the analysis of technical diagnostics system. Due to the distinction between deterministic and random force effects, there have been proposed various methods to distinguish the vibration of informational diagnostic characteristics in order to ensure prompt and reliable detection of the rapidly developing defects. Reliable diagnostics will make it possible to switch from a system of scheduled preventive repairs to the organization of repairs for the current state, with a decrease in the cost of repairing and rebuilding the units of technological complexes by early detection of the defects emerging in the assembly components.On the basis of analyzing the process of propagation of vibroacoustic waves caused by the power action, there has been developed a mathematical model for the emergence and propagation of elastic waves in sophisticated technological complexes from the places of their origin to the point of observation. There have been suggested kinematic schemes for propagation of low-frequency vibrations, vibrosignals from the brush-collector unit, as well as waves from the inner ring of the bearing. This makes possible to substantiate a mathematical model of the occurrence and propagation of vibroacoustic waves in the parts and units of technological complexes from various sources of vibration.The comparative analysis of the research findings on the real vibration fields and the results of numerical modeling confirms the adequacy of the model to the real process. The article presents the graphs of the temporal realization of signals in the model, the spectra of the realized signals, as well as their autocorrelation functions reflecting the main characteristics of the signals at the measurement point. The findings can be used to diagnose and reduce the cost of repair and restoration of the units in sophisticated technological complexes by early detection of the defects emerging in the assembly parts.

Buoyancy-Aided Mixed Convection Between Shear-Thinning Non-Newtonian Nanofluids and Unbounded Elliptic Cylinders in a Vertical Channel

This work presents buoyancy-driven mixed convective flow and heat transfer phenomena of an isothermally heated horizontal elliptic cylinder in vertically upward unbounded flow of power-law type non-Newtonian nanofluids using ANSYS Fluent. The governing continuity, momentum and energy equations for the shear-thinning power-law nanofluids along with suitable boundary conditions are simultaneously solved within the limitations of Boussinesq approximation. The semi implicit method for pressure-linked equations algorithm along with the quadratic upstream interpolation for convective kinematics scheme for discretizing the convective terms in both momentum and energy equations are adopted. The ranges of parameters considered for this study are: volume fraction of nanoparticles, 0.005–0.045; aspect ratio of elliptic cylinder, 0.5–2.5; and Richardson number, 0–40; and a representative Reynolds number of 20. The streamline patterns, surface pressure coefficient distributions, total drag coefficients, isotherm contours, and Nusselt numbers are presented for better understanding of heat transfer and flow phenomena around elliptic cylinders. Briefly results indicate that the total drag coefficient is found to increase with the increasing Richardson number whereas it decreases with the increasing volume fraction of nanoparticles. The average Nusselt numbers are found to increase with increasing Richardson number and increasing volume fraction of nanoparticles.

Solution method of the kinematic function scheme for reconfigurable machine tools based on kinematic transformation

The kinematic function scheme is the basis of the reconfigurable machine tool (RMT) design. However, the diversity and complexity of the scheme are not conducive to the realisation of reconfiguration. To solve this problem, this paper proposes a solution method of the kinematic function scheme based on kinematic transformation. A tool-feature pose matrix is established based on an analysis of the relationship between machining surface features and machining tools to obtain a kinematic function expression that shows the kinematic requirements of the machine tool. The kinematic feature domain and the kinematic transformation domain are used to describe the motion type, motion direction and other information to describe the kinematic parameters of the module. The solution method of the kinematic function chain based on the kinematic decomposition and module combination is proposed to establish the kinematic function scheme of a RMT.