Output Link Research Articles

Anthropomorphic Robotic Eyes: Structural Design and Non-Verbal Communication Effectiveness.

This paper shows the structure of a mechanical system with 9 DOFs for driving robot eyes, as well as the system’s ability to produce facial expressions. It consists of three subsystems which enable the motion of the eyeballs, eyelids, and eyebrows independently to the rest of the face. Due to its structure, the mechanical system of the eyeballs is able to reproduce all of the motions human eyes are capable of, which is an important condition for the realization of binocular function of the artificial robot eyes, as well as stereovision. From a kinematic standpoint, the mechanical systems of the eyeballs, eyelids, and eyebrows are highly capable of generating the movements of the human eye. The structure of a control system is proposed with the goal of realizing the desired motion of the output links of the mechanical systems. The success of the mechanical system is also rated on how well it enables the robot to generate non-verbal emotional content, which is why an experiment was conducted. Due to this, the face of the human-like robot MARKO was used, covered with a face mask to aid in focusing the participants on the eye region. The participants evaluated the efficiency of the robot’s non-verbal communication, with certain emotions achieving a high rate of recognition.

Development of a Dual-Input Magnetic Gear Train for the Transmission System of Small-Scale Wind Turbines

Magnetic gear mechanisms have advanced to have a promising future in transmission technology. Previous research indicates that magnetic gear mechanisms might replace mechanical gear mechanisms in some applications. Small-scale wind turbines (SWT) with counter-rotating rotors that were initially fitted by bevel gears are proposed to be replaced by a coaxial magnetic gear train (CMGT). The CMGT is intended for use as a speed multiplier in order to obtain maximum power at low wind speeds, due to its beneficial transmission of power without physical contact. The primary objective of this study is to build a dual-input CMGT that will be employed in the transmission system of small-scale counter-rotating wind turbines. A dual-input CMGT is built through the analytical modeling of an equivalent magnetic circuit (EMC), which aims to predict the magnetic flux density in the air-gaps of CMGT. Several models within design constraints were compared to obtain the optimum design parameters of the preliminary CMGT design resulting from an EMC analysis. The optimized critical design parameters were then selected and analyzed using finite-element analysis (FEA) to depict the performance of the proposed SWT design. According to the findings, the developed design can generate an inner air-gap flux density of 0.8314 T and an outer air-gap flux density of 1.0200 T. The model likewise produces promising simulation results with an output transmitted torque in the inner rotor (output link) of 8.7 Nm, 56.9 Nm in the outer rotor, and 48.0 Nm in the carrier with pole-pieces. Thus, this design can generate higher torque than a bevel-geared wind turbine. The speed characteristics are also compromised in order to raise the generator’s rotating speed to generate more power. Finally, this study demonstrates the performance and embodiment design of the proposed SWT using CMGT.

Performance analysis of WDM MIMO RoFSO links for 5G applications

The soon to be deployed 5G systems are expected to cater an agglomerate of services at profuse data rates wirelessly. Radio over fiber (RoF) networks are the most suitable to implement such systems. In situations where the practical implementation of RoF systems are non-viable, radio over free space optical (RoFSO) links can be employed. The traditional wavelength division multiplexing (WDM) technology can be incorporated to multiply the data rates. However, the link performance may be degraded due to various atmospheric factors. This can be compensated using multiple input multiple output (MIMO) techniques. In this paper, the performance analysis of such a WDM RoFSO link for 5G frequencies is carried out. The work also presents quantitative performance comparison between single input single output (SISO) and MIMO RoFSO links for 5G systems which will be useful for researchers in this area. It is observed that, while WDM provides additional data capacity, it degrades the link performance under adverse weather conditions which can be counterbalanced using MIMO techniques.

Brexit and labour market inequalities: potential spatial and occupational impacts

Abstract In this paper we examine the possible distributional impacts of new trade barriers associated with the new Trade and Cooperation Agreement governing relations between the UK and EU after Brexit. We use a model of labour demand that incorporates input–output links across industries, and that allows for demand substitution by firms and consumers and worker reallocation across industries. We find that workers’ exposure is moderately increasing across the earnings distribution. Exposure is greater for men than for women as they are more likely to work in manufacturing industries that are relatively harder hit by new trade barriers. Looking across areas, we find that exposure to new Brexit trade barriers is uncorrelated with measures of local deprivation and the impacts of the recent Covid-19 pandemic.

A Reconfiguration Algorithm for the Single-Driven Hexapod-Type Parallel Mechanism

This paper presents a hexapod-type reconfigurable parallel mechanism that operates from a single actuator. The mechanism design allows reproducing diverse output link trajectories without using additional actuators. The paper provides the kinematic analysis where the analytical relationships between the output link coordinates and actuated movement are determined. These relations are used next to develop an original and computationally effective algorithm for the reconfiguration procedure. The algorithm enables selecting mechanism parameters to realize a specific output link trajectory. Several examples demonstrate the implementation of the proposed techniques. CAD simulations on a mechanism virtual prototype verify the correctness of the suggested algorithm.

DTN Architecture With Resource-Aware Rate Adaptation for Multiple Bundle Transmission in InterPlanetary Networks

The world of telecommunications, from some years, is revitalizing an high interest to Deep Space Communication (DSC) and Delay Tolerant Network (DTN) architecture as enabling technologies to offer internet services for aerospace vehicles or orbital stations. The communications between the planets in the solar system is well known to present a series of problems that need to be faced. The fundamental challenge with InterPlanetary Communication (IPC) is the intermittent Line of Sight (LoS) caused by planets movement and the significant propagation time. A possible way to face with it is the use of a DTN approach where routers use a store-and-forward transmission in a hop-by-hop message exchange mechanism. Thanks to this approach, it is possible to face many issues related to the transport layer. The main contribution of this work concerns the proposal of a bundle management layer able to assign at the receiver the appropriate bundle rate on the basis of concurrent bundle transmissions, the output link capacity and buffer resources. The proposed strategy can be integrated with a routing algorithm for InterPlanetary Networks (IPNs) and DTN networks. In our case we consider the Earliest Arrival Optimal Delivery Ratio (EAODR) routing that applies a modified temporal graph to select the IPN nodes. Performance evaluation have been led out to show the benefits of our proposal on the single links and also on the routing scheme in terms of bundle delivery ratio and average bundle delivery time.

Разработка и анализ механизма параллельной структуры, имеющего дугообразные направляющие с прорезями и постоянную точку ввода

The development and study of new mechanisms of a parallel structure ensuring the constancy of the point of instrument entry into the working area is an urgent task of surgery and scientific medicine. A structural synthesis of a parallel structure mechanism designed for robotic laparoscopic surgery has been performed. The proposed mechanism is equipped with arcuate guides with slots installed on the base perpendicular to each other. At the intersection of the slots, there is a bushing through which a straight shaft connected to the output link moves linearly. This arrangement provides a constant entry point, which allows the developed mechanism to be used in laparoscopic surgery and studies of plasma properties. For this mechanism, the inverse problem of positions has been solved, the working area has been determined, and a 3D model has been developed.

Кинематический синтез безмуфтового механического пресса на основе рычажного механизма третьего класса

The article discusses the kinematic scheme of the lever crank-slider mechanism of the third class, on the basis of which the executive mechanism of a mechanical non-clutch press is proposed under the patent for the invention (RF patent No. 2752399). Switching mode of operation of the press is carried out by moving the control slider from one stationary position to another. The kinematic parameters of the lever mechanism are assigned in such a way that in operating mode the law of motion of the working body of the press is close to the law of motion of the output link of the fourlink central crank-slider mechanism, and in the idle mode — the working body makes small movements (approximate stand) at full rotation of the crank. The analytical dependencies necessary for calculating the mechanism and the corresponding example are given.

Synthesis of spatial five- and six-letter mechanisms with rotational pairs by the movement of the output link

The article discusses spatial mechanisms with rotational pairs that allow the movement of the output link or working body with a given accuracy while ensuring the necessary rigidity and reliability of the structure. Its durability is also significantly increased, energy losses are reduced, since all hinge assemblies (rotational kinematic pairs) are made on rolling bearings and are reliably isolated from the external environment. The article is also devoted to the synthesis (design) of functional spatial six-branch mechanisms with rotational pairs reproducing with a given accuracy the linear function of the change in the angle of rotation of the output link, provided it is fully rotatable. The objective function and dependencies necessary for the design of such mechanisms are obtained and an algorithm for solving this problem in CAD is developed.

Кінематичні залежності двокоординатного механізму паралельної структури з поворотним кріпленням шарнірів штанг змінної довжини

In the article the kinematic problem for a new two-axis parallel manipulator with rotary hinged parallelogram, the source of which is a spindle unit, is performed. The analysis of the received kinematic dependencies is carried out. The presence of special provisions of the source body of the mechanism is established. The directions of further scientific researches are outlined. The parallel manipulator structure for consideration differs from previously developed fastenings of hinges of rods of variable length on rotary levers which rotation is coordinated with rotation of an initial link with a spindle unit. On the basis of the developed scheme mathematical dependences for lengths of actuators are established. The performed mathematical transformations allowed to solve direct and inverse kinematic problems for the mechanism. Analysis of the obtained kinematic dependences showed the presence of special positions of the initial body of the mechanism in the form of kinematic parallel singularities. Their graph is given. Graphs of changes of coordinates of an output link at change of lengths of rods of the drive of giving are shown. The analysis of graphic dependences shows existence of such combinations of constructive parameters of the mechanism at which the drive of giving starts to work in a multiplicative mode. The obtained dependences will allow to ensure the functioning of the kinematic circuits of the feed drive of this mechanism. The established points of the kinematic parallel singularity of the feed drive and its operation in the multiplicative mode require further consideration taking into account the dynamic loads. By selecting the design parameters of the mechanism, it is possible to achieve close to rectilinear relationships between changes in the length of the rods and the movement of the spindle unit.

Многокритериальная оптимизация конструкции дельта-робота с четырьмя степенями свободы

A delta robot with three degrees of freedom, having been well studied over the past 40 years, is one of the most popular parallel mechanisms. Nowadays, an urgent task is to study the properties of various modifications of this mechanism. The article considers a delta robot with four degrees of freedom, in which one of the kinematic chains with a parallelogram is divided into two, allowing the output link to have an additional rotational degree of freedom. To maximize the working area and minimize the cost of modification the optimization of the robot design was performed. The problem of maximizing a cubic workspace has been solved.

Исследование кинематических параметров андроидного робота при автоматизированном синтезе движений по вектору скоростей

The modernization of the method of synthesis of motions of manipulators by speed vector allows to exclude motions the emergence of dead ends in the process of computer simulation. The developed algorithm is based on the use of a database characterising the values of kinematic parameters that specify the permissible instantaneous states of the mechanism of the manipulator at different positions. The graphical representation of the hypersurface of the reflective relationship of the specified parameters from the values of the generalized coordinates is made. On the basis of this, a method for determining the above kinematic parameters is proposed, which makes it possible to reduce the time for calculating intermediate configurations on a given trajectory of the output link and to eliminate the occurrence of deadlock situations.

Reduced multibody system transfer matrix method using decoupled hinge equations

AbstractIn the multibody system transfer matrix method (MSTMM), the transfer matrix of body elements may be directly obtained from kinematic and kinetic equations. However, regarding the transfer matrices of hinge elements, typically information of their outboard body is involved complicating modeling and even resulting in combinatorial problems w.r.t. various types of outboard body's output links. This problem may be resolved by formulating decoupled hinge equations and introducing the Riccati transformation in the new version of MSTMM called the reduced multibody system transfer matrix method in this paper. Systematic procedures for chain, tree, closed‐loop, and arbitrary general systems are defined, respectively, to generate the overall system equations satisfying the boundary conditions of the system during the entire computational process. As a result, accumulation errors are avoided and computational stability is guaranteed even for huge systems with long chains as demonstrated by examples and comparison with commercial software automatic dynamic analysis of the mechanical system.

Research of the reliability of a robotic assembly based on the effect of rotation and low-frequency vibrations

Using various physical and technical effects in automatic assembly is a promising tendency to increase the technological reliability of the assembly process. The article presents a method for robotic assembly of cylindrical joints using the effect of rotational motion and low-frequency vibrations. The effect can be achieved by using low-frequency vibrations of the base part with the help of a vibrating device and the rotational movement of the installed part with the help of the rotational movement of the robot out-put link. The paper presented a mathematical model of the dynamics of the robotic assembly process of cylindrical joints. Experiments were set up and carried out to test the effectiveness of the proposed assembly method. The research results affirmed that with a rational technological mode of the robotic assembly process using the effect of rotation and low-frequency vibrations, the probability of jamming is completely eliminated and the assembly force is significantly reduced.

Generalization of Multiplication M-Sequences over Fp and Its Reciprocal Sequences

Mp-Sequences or M-Sequence over Fp not used so much in current time as binary M-Sequences and it is pending with the difficult to construct there coders and decoders of Mp-Sequences further these reasons there is expensive values to construct them but the progress in the technical methods will be lead to fast using these sequences in different life’s ways, and these sequences give more collection of information and distribution them on the input and output links of the communication channels, building new systems with more complexity, larger period, and security. In current article we will study the construction of the multiplication Mp-Sequence {zn}and its linear equivalent, this sequences are as multiple two sequences, the first sequence{Sn}is an arbitrary Mp-Sequence and the second sequence {ζn} reciprocal sequence of the first sequence {Sn}, length of the sequence {zn}, period, orthogonal and the relations between the coefficients and roots of the characteristic polynomial of f(x) and it’s reciprocal polynomial g(x) and compare these properties with corresponding properties in M-Sequences.

Структурный синтез и анализ механизмов с выходным звеном, совершающим одно поступательное и два вращательных движения

The article considers mechanisms based on a hinged flat parallelogram with an additional link, ensuring the ability to maintain the insertion point of the tool installed on the output link. A rotational kinematic pair coupled to the base allows the plane of rotation of the articulated parallelogram to change the angle of inclination. The proposed design should have a greater load capacity than the available analogues, since the rotational kinematic pair mating the articulated parallelogram with the base is made in the form of two semi-axes, and the output link is located between the intermediate links of this parallelogram. The equality of the rotation angles of the output link and the intermediate links of the articulated parallelogram is ensured by the presence of additional links or belt drives. Three-dimensional models of these mechanisms are presented, and their structural synthesis is carried out in various modifications. Depending on the modification, it becomes possible to apply such mechanisms not only in industry, including additive technologies, but also in the field of medicine during surgical operations and in the study of plasma properties.

Влияние точности изготовления планетарно-цевочного редуктора на точность позиционирования робота параллельной структуры

The increased accuracy in high-speed positioning of the parallel robot effector in comparison with that of serial robots with a sequential structure is often the main reason for their use in various modern industries, such as the manufacture of printed circuit boards for microelectronics. However, despite the higher theoretical positioning accuracy, due to the kinematic structure of the parallel robot, in practice this characteristic largely depends on the accuracy of manufacturing individual elements of this mechanism, the most important of which are the gearboxes of the drives of its input pairs. A solution to the urgent problem of determining the effect of the manufacturing accuracy of planetary pinion gearboxes included in the drive of a five-link parallel robot on the positioning accuracy of its output link is proposed. A specific relationship has been determined between the grade of accuracy number of the gear part dimensions and the robot positioning accuracy. The unevenness of the positioning accuracy along the coordinate axes of its working area is revealed. It was found that near the area of certain robot positions the accuracy of its positioning drops sharply.

Моделирование гидропривода с объемным регулированием амфибийного транспортного средства

The article considers a hydraulic drive designed for the fan transmission, which implements the amphibious vehicle chassis on an air cushion. A mathematical model of the dynamics of the hydraulic rotary drive power section with volumetric regulation has been developed. It is proposed to carry out volumetric regulation by means of a directed change in the working volume of the pump. The dynamics of the output link of the hydraulic drive is calculated when a control signal is applied to change the pump washer angle of inclination. The control signal varied from zero to a signal corresponding to 70% of the maximum, and in the range of 70...100%. The basic and structural diagrams of the hydraulic drive are given; its transient characteristics are obtained when the moment of inertia on the shaft of the hydraulic motor changes when the amphibious vehicle is moving. The simulation study focuses on the change in the moment of inertia on the hydraulic motor shaft under various modes of amphibious vehicle movement. The computational studies of the hydraulic drive determine the time of the transient process and the dynamic error. Computational studies of the hydraulic drive revealed its sufficient performance. The use of the developed mathematical model allows choosing the optimal ratio of the hydraulic drive parameters for an amphibious vehicle.

Decentralized uniform finite‐time stabilization of large‐scale nonlinear networks by small‐gain theorems

AbstractWe solve the problem of decentralized uniform finite‐time stabilization for a large‐scale network of nonlinear systems in triangular form which are not feedback linearizable and whose input–output maps are not invertible. For this, we provide a new recursive design to satisfy the conditions of a certain modification of the small‐gain theorems for the case of the uniform finite‐time stability of large‐scale networks. In the general case, we consider the general triangular form systems whose input–output links are surjections only. In addition, we consider the special case of the triangular form systems with polynomial integrators, which is also needed as the first step of the proof of our main result. In the latter case, the design becomes constructive, the decentralized stabilizers can be designed explicitly, and this is demonstrated by examples.

Structural-Parametric Synthesis of the RoboMech Class Parallel Mechanism with Two Sliders

This paper addresses the structural-parametric synthesis and kinematic analysis of the RoboMech class of parallel mechanisms (PM) having two sliders. The proposed methods allow the synthesis of a PM with its structure and geometric parameters of the links to obtain the given laws of motions of the input and output links (sliders). The paper outlines a possible application of the proposed approach to design a PM for a cold stamping technological line. The proposed PM is formed by connecting two sliders (input and output objects) using one passive and one negative closing kinematic chain (CKC). The passive CKC does not impose a geometric constraint on the movements of the sliders and the geometric parameters of its links are varied to satisfy the geometric constraint of the negative CKC. The negative CKC imposes one geometric constraint on the movements of the sliders and its geometric parameters are determined on the basis of the Chebyshev and least-square approximations. Problems of positions and analogues of velocities and accelerations of the considered PM are solved to demonstrate the feasibility and effectiveness of the proposed formulations and case of study.