Structure Of Industrial Robot Research Articles

Feature fusion and distillation embedded sparse Bayesian learning model for in-situ foreknowledge of robotic machining errors

In recent years, robotic machining of complex surface has become a research hotspot for intelligent manufacture. Considering the weak rigidity characteristics of industrial robot structure, the machining errors will be generated during the robotic machining process, which will further induce the undesirable impact on machining quality and production cycles. Therefore, this work proposes an in-situ foreknowledge model for robotic machining errors of complex curved parts. The static and dynamic features during the robotic manufacture process are obtained, where the robots’ stiffness concerning end effect operator is extracted as the static features, as well as the dynamic features of the monitored dynamic cutting forces. Furthermore, the structured fusion features are utilized as the dataset to train the foreknowledge model based on sparse Bayesian learning method. In order to adapt to the rapid response in the industrial field, the principal component analysis strategy is adopted to reduce feature dimension, by which the complexity of fusion features is reduced by 50.51 %. In addition, based on the adjustment of sparse weights, the complexity of the sparse Bayesian foreknowledge model is reduced by 74.31 %. According to the validation experiment on the blade shaped workpiece of marine propeller, the results indicate that the prediction accuracy of the proposed in-situ foreknowledge model is in the range of 60.03–87.07 µm, meeting the engineering requirements of robotic machining errors. The proposed in-situ foreknowledge sparse model displays the potential prospects for robotic machining errors prediction and control in the industrial application field.

Organisation and Principle Design of a Flexible Manufacturing Cell Dedicated to the Annual Overhaul Activities for TAB-77

Abstract In this scientific paper, aspects of the design, calculation and implementation of an industrial robot, designed in a modular-serial construction, in a flexible cell for annual overhaul operations of the TAB-77 armored amphibious transporter are highlighted. The scientific approach is based on the following aspects: presentation of some peculiarities of the implementation of advanced technologies in the field of maintenance operations, optimal choice of an industrial robot structure that will serve the flexible cell, matrix calculation related to the direct and inverse geometric model for determining the workspace, configuration of the flexible cell and elements of economic calculation of the entire flexible system proposed through the authors. The scientific itinerary concludes with the presentation of some conclusions resulting from the study performed and some proposals and perspectives for further development of the solution presented.

Joint feature enhancement mapping and reservoir computing for improving fault diagnosis performance

Complicated industrial robot structure and harsh working conditions may cause signal features collected in the condition monitoring process to be seriously disturbed. In this paper, a joint feature enhancement mapping and reservoir computing (FEM-RC) method is presented to handle the industrial robot fault diagnosis problem. Firstly, a feature enhancement mapping (FEM) method is proposed to achieve intraclass distance minimization and interclass distance equalization to obtain an enhanced feature matrix. Then, the first reservoir computing (RC) network is adopted to map the original feature matrix to the feature enhancement matrix, and the second RC network is for fault type classification. The results of the experiment carried out on a six-axial industrial robot demonstrate that compared with other peer models, the present FEM-RC has better fault diagnosis performance and robustness.

New 5-DOF Industrial Robot Structure, Modeled and Optimized by the Finite Element Method

New 5-DOF Industrial Robot Structure, Modeled and Optimized by the Finite Element Method

Effect of axial vibrations on regenerative chatter in robotic milling

The highly flexible structure of industrial robots introduces new challenges to modeling vibrations during robotic milling processes. This paper studies the contribution of the axial vibrations of the milling end-effector to regenerative chatter in robotic milling. While axial vibrations of the tool are usually neglected in standard CNC machines, in industrial robots, they may significantly affect the stability of the process. The numerical case studies in this work show that the modulation of the nominal depth of cut due to axial vibrations may cause nonlinearities in the cutting forces. In addition, it is also shown that axial vibrations may cause the feed-generated and edge forces to affect the stability of regenerative vibrations in robotic milling.

The Seednoid Robot Platform: Designing a Multipurpose Compact Robot From Continuous Evaluation and Lessons From Competitions

Robots are designed to tackle specific problems or are designed as a multipurpose platform that achieves a concept. In this letter, we approach the hardware design problem from practice and evaluation through numerous competitions including the Darpa Robotics Challenge, the Amazon Picking Challenge, and other competitions that were held in Japan. The paper aims to answer the question what hardware design would we achieve if we continuously refine designs through competitions? We show that competitions lead to a more compact but capable platform design that is durable and has more end effector solutions. We also point out the limitations and benefits of using competitions for designing robot platforms. Our platform began from a human-inspired design for teleoperation and has evolved to mix both human-like and industrial robot structure.

A Review on Chatter in Robotic Machining Process Regarding Both Regenerative and Mode Coupling Mechanism

During the last few decades, industrial robots have been widely used in various applications to develop a flexible and efficient manufacturing process such as material handling and welding. However, as a high value-added application, few robotic machining systems have been installed mainly due to the limitation from the chatter, which leads to the poor product quality and low productivity. Although researchers have been continuously investigating the robotic machining chatter, there is still a lack of understanding due to the complexity of the issue. This paper provides a comprehensive review on chatter-related issues during robotic machining tasks, including mechanisms, mitigation strategies, and identification methods regarding both regenerative chatter and mode coupling chatter. Due to the low stiffness and couple structure of industrial robots, both regenerate and mode coupling chatter can occur at different cutting conditions. The difference between two chatter mechanism in the robotic machining process are compared and a list of guidelines is provided to help in distinguishing these two types of chatter. Systemic analysis of the mechanisms of the chatter identification and suppression is presented providing a research basis for future studies.

The influence of reference position deviation on industrial robots positioning precision

Due to industrial robot’s higher precision and better repeatability that human workforce, they have been chosen to replace human workload in all types of industrial activities. Due to the increasing positioning precision and repeatability needed by the industrial operations, it is necessary to use industrial robots that comply with the required technical specifications. For this reason, research on new methods to increase positioning accuracy is necessary. Some of the positioning errors are caused by the reference positioning deviations present in the industrial robot structure. Due to the systematic nature of reference position deviations, by entering the values in a compensation method, the positioning error is permanently minimized. In the paper are presented new methods of reference positioning deviations determination. In the paper is presented a mathematical model based on direct kinematic modeling method, used for calculating the position of the industrial robot end-effector. By applying these method’s, we can determine the reference positioning deviations and by introducing them into a specialized calculation system we can simulate the impact of these deviations. By applying these methods on a six axis articulated industrial robot and introducing the industrial robot’s parameters in a specialized calculating programs the positioning errors are determined and shown in the paper.

Construction typification as the tool for optimizing the functioning of a robotized manufacturing system

Process of workcell designing is limited by different constructional requirements. They are related to technological parameters of manufactured element, to specifications of purchased elements of a workcell and to technical characteristics of a workcell scene. This shows the complexity of the design-constructional process itself. The results of such approach are individually designed workcell suitable to the specific location and specific production cycle. Changing this parameters one must rebuild the whole configuration of a workcell. Taking into consideration this it is important to elaborate the base of typical elements of a robot kinematic chain that could be used as the tool for building Virtual modelling of kinematic chains of industrial robots requires several preparatory phase. Firstly, it is important to create a database element, which will be models of industrial robot arms. These models could be described as functional primitives that represent elements between components of the kinematic pairs and structural members of industrial robots. A database with following elements is created: the base kinematic pairs, the base robot structural elements, the base of the robot work scenes. The first of these databases includes kinematic pairs being the key component of the manipulator actuator modules. Accordingly, as mentioned previously, it includes the first stage rotary pair of fifth stage. This type of kinematic pairs was chosen due to the fact that it occurs most frequently in the structures of industrial robots. Second base consists of structural robot elements therefore it allows for the conversion of schematic structures of kinematic chains in the structural elements of the arm of industrial robots. It contains, inter alia, the structural elements such as base, stiff members - simple or angular units. They allow converting recorded schematic three-dimensional elements. Last database is a database of scenes. It includes elements of both simple and complex: simple models of technological equipment, conveyors models, models of the obstacles and like that. Using these elements it could be formed various production spaces (robotized workcells), in which it is possible to virtually track the operation of an industrial robot arm modelled in the system.

Vibration Analysis on the Structure of the Robot Yamaha YK 400

The purpose of this paper is to analyze the behavior of the industrial robot Yamaha YK400, SCARA model, used in machining operations (drilling, milling, deburring). In the industrial robot structure was integrated a mill Lund 79314. The mechanical structure of the robot is under the influence of vibration during the milling process. This paper aims to determine the process parameters vibrational based on the position of the characteristic point, speed milling and material. To achieve the intended purpose, we used a data acquisition system composed of acceleration sensor, acquisition boards, LabView. The obtained results were analyzed and interpreted.

Optimization Trajectory in Handling with the Same Object

In this paper, there is presented an industrial robot trajectory optimization method for series of point-to-point type movements. Also contain an optimization strategy that has been built using through proposed automated optimizing system for handling. The optimized trajectories must lead to avoid exciting mechanical resonance modes of the industrial robot structure. This can be achieved by applying of robot interpolation. The testing results show that the trajectory optimization through this method is feasible for industrial robots.

Evolutionary Optimum Design for a Task Specified 6-Link Planar Robot

Optimal structure design for robots is fundamentally important, as it stands first in the order of robotic system design. The structure of industrial robots should be robust, versatile and strong enough – to withstand a variety of forces/loads, guarantee stability and security in operation. To achieve best solution, it is desirable to perform structure design optimization. Here, it is proposed to determine optimal geometric dimensions for a task specified 6-link planar robot considering pick and place operation. The aim is to minimize torque required for defined motion and to maximize manipulability measure of the robot subject to dynamic, kinematic, deflection and structural constraints. Links physical characteristics (length and cross sectional area parameters) are design variables. Five different cross-sections (hollow circle, hollow square, hollow rectangle, C-channel and I-channel) have been experimented for the link. Evolutionary algorithms viz. Elitist Nondominated Sorting Genetic Algorithm (NSGA-II) and Multi Objective Differential Evolution (MODE), Multiobjective Genetic Algorithm (MOGA) are used. Normalized weighting objective functions and average fuzzy membership functions are used to select the best optimal solution. Multiobjective performance measures, namely, Solution Spread Measure (SSM) and Ratio of Non-dominated Individuals (RNI) are used to evaluate Pareto optimal fronts. Two other multiobjective performance measures, namely, Optimizer Overhead (OO) and Algorithm effort are used to find computational effort of optimization algorithms. Results obtained from various techniques are compared and analyzed.

Aspects on the Calculus and Construction of Translation Modules in the Mechanical Structure of an Industrial Robot Possessing Four Degrees of Freedom

The authors of this paper wish to highlight elements specific to the dynamic calculus, the concept, optimal design and assembly of translation modules in an industrial robot architecture of serial-modular construction, a structure which possesses in its kinematic chain structure four degrees of freedom. Based on a rigorous dynamic study conducted on the mechanical structure of the TTRT type industrial robot, modelling performed using Lagrangian formalism, and, taking into account the organological design elements that are part of the translation modules (the module attached to the robotic base - MTB Sil, the module in the vertical robotic arm MTV Sil, and the module in the mechanical structure of the horizontal robotic arm - MT Sil), the authors propose an energetic method of constructive optimization of the mechatronics system, according to which, translation modules can be arranged by applying the principle of interchangeable modularity so that energy consumption be minimum and not intervene on their organology. The paper highlights the dynamic-organological algorithm proposed in order to calculate motor moments and, hence, the selection of the DC servomotors necessary for setting the translation movable systems into service.

Design of a Driving Kinematical Joint Actuated with Intelligent Materials Used in Structure of Industrial Robots

The paper presents the design of a driving kinematical joint driven by a shape memory alloy actuator, which has the capacity to ensure a control of displacements and of forces in both directions. There are presented some aspects regarding the main designing elements of the driving kinematical joint and of the actuator. The constructive solution, an original conception, presents a series of advantages. Thus, the use of electric, hydraulic or pneumatic engines or machines was eliminated, decreasing the weight and size of the driving kinematical joint, decreasing the energetic consumption, having a simple and viable construction. In order to verify the presented device functionality the numerical simulation method of specialized SolidWorks software was used.

Feed-Forward Compensated PD Controller and PD Robust Controller Simulation Comparison on Uncertain Single-Manipulator

2D rotary robotic manipulator is an ordinary mechanical structure of industrial robot. PD control is an ever-developing method for the dynamic characteristics controlling. By the co-simulation on ADAMS and Matlab/Simulink, the paper designs a feed-forward compensation PD controller and PD robust controller based on single-manipulator model and completes track and velocity control trial respectively. Through result comparison and analysis, the superiority of PD robust controller for uncertain single-manipulator is verified.

Aspects on the Functional Optimization of an Industrial Robot Structure Implemented in Military Logistical Activities

AbstractThe authors of the present paper outline aspects on the optimization of the a TR‐type industrial robot structure movements in order to generate the manipulation space to a flexible manufacturing cell with a parallel organization designed for the pallet and container operation of paint‐filled recipients. The paper contains the direct and inverted geometrical modelling of the robot structure using the 3*3 rotation matrix method and the algebra method. After knowing the characteristic point movement of the prehension device, graphics for the variation of the TR robot's general coordinates and for the trajectory of the prehension device's characteristic point of its work space were performed by using the Mathematica 6.0 soft. (© 2011 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Temperature Effects on Performance of Industrial Robots Made of Composite Materials

Industrial Robots design is always a challenge in terms of the materials being chosen for manufacturing the mechanical elements of the robots. The present paper is a theoretical study on the effects of temperature to the positioning precision of the robots with mechanical elements having composite materials in their structure. A case study was made on a SCARA industrial robot structure.

COMPARATIVE ANALYSIS FOR LINK CROSS-SECTION OF MANIPULATOR ARMS

The stresses and deflections in robot arm was analyzed using ANSYS software package. Industrial robot analyzed in this work consists of three arms that have 2-DOF. The analysis of eacharm had been made separately. The maximum stress and deflection have been analyzed for a static applied at one end of the arm while has the other end fixed. Links of various cross-sections having same masses, length, and material properties to make a choice of the shape that gives a high stiffness to weight ratio have been examined. After specifying the best section for the arms of the robot an optimization process began to determine the dimensions of the arms sections which give the least deformation this had been done by the aid of a program build up by using the MATHCAD software package. In the beginning the program finds the optimum section in which the stress in the members not exceeds the allowable stress and finds the total weight of the robot after that the program begins to change the dimensions to satisfy the condition of minimum deflection of the whole robot after that the program estimates the best choices of the dimension for each section that gives the minimum weight and deflection. The dynamic behavior of the best chosen structure of industrial robot was studied to find the natural frequencies ( n w ) and mode shapes. The result shows that the hollow circular section is the best section for the first link while a square section is the best section for the other two links.

Symbolic structural synthesis and a description method for planar kinematic chains in robotics

A new method for structural synthesis of planar link chains in robotics is presented. It is based on the notion of logical equations associating Modular Structural Groups (MSGs) and closed chains. After a brief reminder of the theory of MSGs, and of connectivity and mobility laws, various levels of abstraction are studied concerning the structural number. This permits the synthesis of planar chains with various degrees of complexity. The logical equation notion is introduced. It permits the association of MSG of type A and closed chains of type G. A method for the description of chains by contours and molecules is also proposed. It permits the classification of topological robot structures taking into account their complexity expressed by the number of closed loops in their molecules. This method is applied for the description of chains thus obtained, and for the description of the main structure of industrial robots with closed planar chains.

Concept of a robot for interior building trades by the example of wall slits in masonry

This article that is taking pattern from a presentation held at the 13th ISARC in Tokyo deals with the automation of interior building trades by the use of robots [1]. Therefore, the specifications of a robot system for the manufacturing of wall slits, as a preliminary step of wiring and electrical installations in masonry construction, will be defined. The main motivation to reduce the manual tasks is the great difference between the high qualification of workers (especially electricians) and partly the unpretending hard work that does not require such a professional education in the same way. So, the focus of the article lays on a manufacturing process that is suitable for automation, kinematical concepts for the robot and the development of an appropriate end effector. The requirements of the closeness of space and light weight result in the necessity of other kinematical concepts and structures, because common structures of industrial robots are not suitable. The presented kinematics are based on linear components as best solution to cope with the two-dimensional area and a special developed wrist to bridge the existing clearance volumes of the main axes and to allow the accessibility of corners. Furthermore, the robot has to be able to reach working heights near to ceilings and simultaneously to pass a door. Besides this, a robotized process will be explained in order to reduce manual refinishing operations as much as possible because of economical reasons. Consequently, the design of an appropriate end effector based on a joint cutter will be shown. Finally, the sequence of work preparation tasks for the set-up of the robot will be described and a proof for the efficiency of the system will be given.