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Journal articles on the topic 'Two-axis manipulator'
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1
Pan, Xiao Bin, Yong Tao Li, and Rong Zhou. "Research on Automatic Tape Vulcanizing Tank Hoisting Manipulator Based on PLC." Applied Mechanics and Materials 373-375 (August 2013): 271–74. http://dx.doi.org/10.4028/www.scientific.net/amm.373-375.271.
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In this paper, an automatic tape vulcanizing tank hoisting manipulator is designed to improve the accuracy and the efficiency in tape vulcanization. The hoisting manipulators control system takes Siemens S7-200 PLC as the core. By controlling two frequency converters and a solenoid valve, the hoisting manipulator not only movs along the Y-axis and Z-axis also clamps the vulcanizing mold. In addition, the hoisting manipulator communicates with the vulcanizing tank through PC / PPI bus and the RS232/485 interface port on PLC, achieving linkage production.
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Chalhoub, Nabil G., and Xiaoying Zhang. "Reduction of the End Effector Sensitivity to the Structural Deflections of a Single Flexible Link: Theoretical and Experimental Results." Journal of Dynamic Systems, Measurement, and Control 115, no. 4 (December 1, 1993): 658–66. http://dx.doi.org/10.1115/1.2899193.
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The fine positioning problem of the gripper of flexible robotic manipulators is addressed in this study. A two-axis cartesian micro-manipulator is implemented to reduce the sensitivity of the gripper to the structural deformations of a single flexible link. A laser head with a dual axis photodetector are used to provide direct measurements of the transverse deflections at the free-end of the beam and to detect mechanical inaccuracies caused by manufacturing imperfections and assembly misalignment. The advantages of the integrated system of the micro-manipulator with a single compliant beam are demonstrated and compared to the one without the micro-manipulator for two different control schemes, “rigid body controller (RBC)” and “rigid and flexible motion controller (RFMC).” Both theoretical and experimental results have proven the capability of the micro-manipulator in significantly improving the gripper positional accuracy. Furthermore, it was demonstrated that the micro-manipulator tends to complement rather than overlap the efforts exerted by the host beam controller.
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Chen, Wen Jia, Yan Zhong He, and Jiang Zhang. "A Four Degrees of Freedom Parallel Manipulator for Machining." Advanced Materials Research 139-141 (October 2010): 2168–71. http://dx.doi.org/10.4028/www.scientific.net/amr.139-141.2168.
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In the past decades, a number of parallel manipulators have been extensively studied. However, most efforts are dedicated to six degrees of freedom (DOF) or three-DOF manipulators. There is a need for equipment providing more than three DOF's arranged in parallel and based on simpler arrangements than six-DOF arrangements in application. This paper presents a novel four-DOF parallel platform manipulator with base mounted prismatic actuators. The manipulator is driven by four linear actuators. The movable platform of the manipulator can translate along two directions and rotate around two axes respectively. The kinematics model is formulated, which describes the inverse and forward kinematics transformation. It is very easy to develop a five-axis NC machine-tool which is of large-workspace based on the four-DOF parallel mechanism presented in this paper.
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Hao, Guangbo, and Xianwen Kong. "A structure design method for compliant parallel manipulators with actuation isolation." Mechanical Sciences 7, no. 2 (November 30, 2016): 247–53. http://dx.doi.org/10.5194/ms-7-247-2016.
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Abstract. Since precise linear actuators of a compliant parallel manipulator suffer from their inability to tolerate the transverse motion/load in the multi-axis motion, actuation isolation should be considered in the compliant manipulator design to eliminate the transverse motion at the point of actuation. This paper presents an effective design method for constructing compliant parallel manipulators with actuation isolation, by adding the same number of actuation legs as the number of the DOF (degree of freedom) of the original mechanism. The method is demonstrated by two design case studies, one of which is quantitatively studied by analytical modelling. The modelling results confirm possible inherent issues of the proposed structure design method such as increased primary stiffness, introduced extra parasitic motions and cross-axis coupling motions.
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de Almeida, F. Gomes, and K. A. Edge. "Decentralized Adaptive Control of a Directly Driven Hydraulic Manipulator: Part 2: Experiment." Proceedings of the Institution of Mechanical Engineers, Part I: Journal of Systems and Control Engineering 209, no. 3 (August 1995): 197–205. http://dx.doi.org/10.1243/pime_proc_1995_209_384_02.
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The implementation of a decentralized model reference adaptive control scheme for a two-axis robotic manipulator is described. It is shown, through an extensive series of experiments, that very good model-following performance and axis decoupling is achieved regardless of manipulator payload and working position.
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Kim, Dong Hong, Dong Won Jung, and Choon Man Lee. "Study on Angle Calculation of Two-axis Manipulator for Laser Assisted Machining." Journal of the Korean Society for Precision Engineering 31, no. 2 (February 1, 2014): 113–17. http://dx.doi.org/10.7736/kspe.2014.31.2.113.
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Amine, Semaan, Mehdi Tale Masouleh, Stéphane Caro, Philippe Wenger, and Clément Gosselin. "SINGULARITY ANALYSIS OF THE 4 RUU PARALLEL MANIPULATOR USING GRASSMANN-CAYLEY ALGEBRA." Transactions of the Canadian Society for Mechanical Engineering 35, no. 4 (December 2011): 515–28. http://dx.doi.org/10.1139/tcsme-2011-0031.
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This paper deals with the singularity analysis of four degrees of freedom parallel manipulators with identical limb structures performing Schönflies motions, namely, three independent translations and one rotation about an axis of fixed direction. The 6 × 6 Jacobian matrix of such manipulators contains two lines at infinity among its six Plücker vectors. Some points at infinity are thus introduced to formulate the superbracket of Grassmann-Cayley algebra, which corresponds to the determinant of the Jacobian matrix. By exploring this superbracket, all the singularity conditions of such manipulators can be enumerated. The study is illustrated through the singularity analysis of the 4-RUU parallel manipulator.
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Kohli, D., Soo-Hun Lee, Kao-Yueh Tsai, and G. N. Sandor. "Manipulator Configurations Based on Rotary-Linear (R-L) Actuators and Their Direct and Inverse Kinematics." Journal of Mechanisms, Transmissions, and Automation in Design 110, no. 4 (December 1, 1988): 397–404. http://dx.doi.org/10.1115/1.3258936.
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In this paper, a new type of two-degree-of-freedom actuator called the rotary-linear (R-L) actuator is described. The R-L actuator permits a rotation and a translation along the axis of rotation, thus simulating a cylinder pair. The R-L actuators are then used in type synthesis of mechanical manipulator chains. Closed-loop three-, four, five, and six-degree-of-freedom chains containing four to nine links, R-L actuators, revolute pairs (R), prismatic pairs (P), cylindrical pairs (C), and spheric pairs (S) are then obtained. A class of manipulator configurations where the hand is connected to the ground via six-degree-of-freedom dyads or triads and containing three grounded R-L actuators is treated for inverse kinematics. Since all the actuators are on the ground in this configuration, higher payload capacities and smaller actuator sizes can be expected from these configurations. In addition, generally, the computations required for inverse kinematics are also significantly less than those required for serial link open-loop manipulators. The direct kinematics, however, is much more involved and computationally intensive for these manipulators than for serial-link manipulators. The direct kinematics of an example manipulator is derived and requires solution of a 16th-order polynomial equation. Numerical examples are presented for illustration.
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Hurski, N. N., Yu A. Skudnyakov, V. S. Artsiushchyk, and A. N. Bezruchko. "Control of Mechatronic System Based on Multilink Robot-Manipulators." Science & Technique 18, no. 4 (August 13, 2019): 350–54. http://dx.doi.org/10.21122/2227-1031-2019-18-4-350-354.
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The task of controlling multi-link robots with manipulators for implementation of high-tech processes in industry has been considered in the paper. The paper presents sequential steps of using computer technology in construction of robotic-manipulators, including mathematical, algorithmic, and hardware and software tools for creating a multi-drive mechatronic system controlled by OMRON industrial microcontroller. A kinematic scheme of a robot manipulator has been described in the paper and it performs the following two types of movements – rotation around the z axis and rectilinear movement of a working element along a turning radius with precise positioning at a given point in the working space. Electromechanical design of the manipulator allows to ensure transportation of production objects in accordance with a given technological process. For designing the technological process of transporting production objects, a software module has been developed that makes it possible to automate description of basic operations for movement of the robot manipulator working body with subsequent automatic generation of a command sequence for a control program ensuring operation of electric drives in manipulator links in real time. To speed up the process of designing trajectory of the working body, a spatial simulation model of a robot-manipulator in the MatLab-Simulink environment has been developed. The paper considers a generalized diagram of a mechatronic control system for a robot-manipulator based on the OMRON programmable logic controller operating under control of a program developed in the programming environment Sysmac Studio Automation. A program for a programmable terminal with interface elements and animation elements has been developed for industrial use of the mechatronic system during adjustment and operation period. The paper provides an appearance of a robot-manipulator prototype. The developed mechatronic system of the robot-manipulator can be technologically oriented towards solving other problems of industrial production.
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Meckl, P., and W. Seering. "Active Damping in a Three-Axis Robotic Manipulator." Journal of Vibration and Acoustics 107, no. 1 (January 1, 1985): 38–46. http://dx.doi.org/10.1115/1.3274714.
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This paper explores several methods to eliminate residual vibration of a robot arm at the end of a move, using open-loop control. The robot structure is modeled as lumped masses and springs with negligible damping, representative of a three-axis Cartesian manipulator. Vibration control is achieved using two different types of forcing functions: (1) a “bang-bang” control function for time-optimal response, and (2) a function constructed to avoid exciting resonance throughout the move. These functions are then compared in their ability to attenuate residual vibration in practice and the response time using (2) is compared with the optimal time using (1).
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Sun, Dong, Y. X. Su, and James K. Mills. "Position Control of Direct-Drive Robot Manipulators with PMAC Motors Using Enhanced Fuzzy PD Control." Journal of Advanced Computational Intelligence and Intelligent Informatics 8, no. 3 (May 20, 2004): 324–31. http://dx.doi.org/10.20965/jaciii.2004.p0324.
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A position control approach for direct-drive robot manipulators with permanent magnet AC (PMAC) motors is proposed. The conventional vector control architecture has been simplified by specifying the motor stator phase so that the rotating d-axis current is zero. The position control is designed to be an enhanced fuzzy PD controller, by incorporating two nonlinear tracking differentiators into a conventional fuzzy PD controller. The proposed control methodology is easy to implement, and exhibits better control performance than conventional control methods. Experiments conducted on a single-link manipulator directly driven by a PMAC motor demonstrate the validity of the proposed approach.
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KANEKO, Tomoaki, Takaji UMENO, and Yoichi HORI. "Motion Control of Multi-Axis Manipulator Using Robust Servo System with Two Degrees of Freedom." Journal of the Robotics Society of Japan 9, no. 7 (1991): 830–40. http://dx.doi.org/10.7210/jrsj.9.830.
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Kim, Dong-Hyeon, Na-Hyeon Cha, Tae-Woo Kim, and Choon-Man Lee. "A Fundamental Study on the Design of Two-axis Drive Manipulator for Laser-assisted Machining." Journal of the Korean Society of Precision Engineering 29, no. 8 (August 1, 2012): 813–17. http://dx.doi.org/10.7736/kspe.2012.29.8.813.
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Postigo, José F., Vicente A. Mut, Ricardo O. Carelli, Luis A. Baigorria, and Benjamin R. Kuchen. "Hand controller for bilateral teleoperation of robots." Robotica 18, no. 6 (November 2000): 677–86. http://dx.doi.org/10.1017/s0263574700002782.
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Teleoperation, one of the oldest areas of robotics, has experienced considerable growth in the last two decades. Main causes for this trend are the need for increased safety levels for human operators and lower production costs. In this work, a three d.o.f. local manipulator (two d.o.f. for force and one d.o.f. for torque) is developed. This hand controller, intended for robot or mobile teleoperation systems, has force reflection in two axes and torque reflection in the third axis. using a robotic hand developed at INAUT as a remote device, laboratory experiments on each axis (one at a time) have shown good results. An impedance controller at the remote system allows one to carry out interactive tasks with the environment such as polishing, insertion and grinding, where it is necessary to control and accommodate the interaction forces and torques in order to avoid hazards for both the manipulated objects and the remote robot.
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Mansour, Nader A., Buhyun Shin, Bongjo Ryu, and Youngshik Kim. "Development of a Novel Miniaturized Electromagnetic Actuator for a Modular Serial Manipulator." Actuators 10, no. 1 (January 14, 2021): 14. http://dx.doi.org/10.3390/act10010014.
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This paper presents a novel miniaturized and modular dual-axis Electromagnetic Actuator (EMA). It mainly consists of two electromagnetic coils in an orthogonal orientation with a permanent magnet fixed on a free moving frame that rotates around two axes/joints. By actuating either of the coils, the free moving frame rotates around the corresponding axis. Simulations and experimental analyses are conducted in order to characterize the performance of our EMA. Thus, our actuator achieves a torque of 100 mNm at simulation and 80 mNm through experimentation for the same applied current. Additionally, it can achieve a rotation of 10∘ (≈0.2 rad), according to simulations and experimental work. Because of modularity, multiple units of our EMA can be connected together in different configuration to serve in several applications. As an example application, we used a pair of our EMA in order to generate a miniaturized 4-DOF robotic manipulator. This manipulator demonstrates the advantages of light weight, small size, and a high level of manipulability. Kinematic analyses and experimental work are performed in order to validate our manipulator and to prove the concept of our proposed EMA. Through this experiment, we applied an open-loop controller on our EMAs, so that the end-effector of our manipulator can track a predefined circular trajectory. The movement of the end-effector is detected while using image processing techniques. Although we used an open-loop controller, our manipulator is still able to track the trajectory with moderate errors.
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Ciliz, M. Kemal, and M. Ömer Tuncay. "Comparative experiments with a multiple model based adaptive controller for a SCARA type direct drive manipulator." Robotica 23, no. 6 (November 2005): 721–29. http://dx.doi.org/10.1017/s026357470500158x.
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In this paper, different adaptive control algorithms will be experimentally tested on a two axis SCARA type direct drive robot arm, and the performance of these algorithms will be compared. Being a direct drive system, the nonlinear effects, arising from the dynamics of the manipulator under high velocities, are directly reflected in the control of the manipulator. This makes the manipulator a more efficient test bed for testing the efficiency of the proposed adaptive schemes. In the experiments, we used fast trajectories rather than slow ones to observe how the proposed controllers compensate the dynamic nonlinear effects of manipulator dynamics. We will test some known adaptive control algorithms given in the literature along with our proposed adaptive control scheme which makes use of multiple models.
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Chen, Wen Jia, and Lan Lei Zhao. "A New 2T-2R Hybrid Parallel Manipulator." Advanced Materials Research 328-330 (September 2011): 1743–46. http://dx.doi.org/10.4028/www.scientific.net/amr.328-330.1743.
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Though computer technology has brought about virtual manufacturing to expedite design and analysis through simulation and visualization, machines remain essential, as ultimately products need to be made. There is a need for equipment providing more than three degrees of freedom (DOF) arranged in parallel and based on simpler arrangements than 6-DOF arrangements in application. This paper presents a new 4-DOF hybrid parallel platform manipulator with fixed-leg lengths and base mounted prismatic actuators. The movable platform of the manipulator can translate along two directions and rotate around two axes respectively (2T-2R). The kinematics model is formulated, which describes the inverse and forward kinematics transformation. It is very easy to develop a 5-axis NC machine-tool which is of large-workspace based on the 2T-2R, 4-DOF parallel mechanism presented in this paper.
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Suarez, Alejandro, Manuel Perez, Guillermo Heredia, and Anibal Ollero. "Cartesian Aerial Manipulator with Compliant Arm." Applied Sciences 11, no. 3 (January 22, 2021): 1001. http://dx.doi.org/10.3390/app11031001.
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This paper presents an aerial manipulation robot consisting of a hexa-rotor equipped with a 2-DOF (degree of freedom) Cartesian base (XY–axes) that supports a 1-DOF compliant joint arm that integrates a gripper and an elastic linear force sensor. The proposed kinematic configuration improves the positioning accuracy of the end effector with respect to robotic arms with revolute joints, where each coordinate of the Cartesian position depends on all the joint angles. The Cartesian base reduces the inertia of the manipulator and the energy consumption since it does not need to lift its own weight. Consequently, the required torque is lower and, thus, the weight of the actuators. The linear and angular deflection sensors of the arm allow the estimation, monitoring and control of the interaction wrenches exerted in two axes (XZ) at the end effector. The kinematic and dynamic models are derived and compared with respect to a revolute-joint arm, proposing a force-position control scheme for the aerial robot. A battery counterweight mechanism is also incorporated in the X–axis linear guide to partially compensate for the motion of the manipulator. Experimental results indoors and outdoors show the performance of the robot, including object grasping and retrieval, contact force control, and force monitoring in grabbing situations.
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Thanh, Tu Diep Cong, and Kyoung Kwan Ahn. "Control of two-axis pneumatic artificial muscle manipulator with a new phase plane switching control method." Journal of Mechanical Science and Technology 21, no. 7 (July 2007): 1018–27. http://dx.doi.org/10.1007/bf03027651.
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Qian, Jun, Hua Bing Zhu, Shu Wang Wang, and Yi Shan Zeng. "A 5-DOF Combined Robot Platform for Automatic 3D Measurement." Key Engineering Materials 579-580 (September 2013): 641–44. http://dx.doi.org/10.4028/www.scientific.net/kem.579-580.641.
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This paper describes the reconstruction process of a 3P2R type combined robot platform on the basis of a 2-axis linearly moving worktable. An additive 3-DOF manipulator installed above the worktable has one prismatic and two revolute joints by using a novel integrated ball screw and spline axis. The control system of the platform is composed of a 4-axis motion control card and a PLC. Meanwhile, this paper deduces the kinematic equations of this special combined platform for measurement. The 3P2R type platform could be used to measure 3D contour of small work piece automatically.
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Faraz, Ali, and Sharam Payandeh. "Kinematic modelling and trajectory planning for a tele-laparoscopic manipulating system." Robotica 18, no. 4 (July 2000): 347–60. http://dx.doi.org/10.1017/s026357479900209x.
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This paper addresses the kinematic modelling, solutions and trajectory planning of a tele-laparoscopic manipulator. This type of manipulator can be used in remote positioning of laparoscopic tools through tele-operating system. Specifically the paper models kinematics of a typical manipulating system which can be used in such tele-surgery. Inverse kinematics solutions are also obtained for two kinematically constraint motions which are part of a typical trajectory of the laparoscopic tools. These are fixed axis rotation of the tool and its straight line motion. Simulation results are presented to demonstrate the validity of such models and solutions.
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Wang, Xiao Lin, Xiao Shi Wang, Ai Xiang Wei, and Ke Tian Li. "Application of the Two-Dimensional Movement and One-Dimensional Rotation 3 DOF Robot on Riveting System." Key Engineering Materials 522 (August 2012): 649–53. http://dx.doi.org/10.4028/www.scientific.net/kem.522.649.
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This paper presents a two-dimensional movement and the one-dimensional rotating 3 DOF robot that can be used to pick up, delivery and place riveting column, thin axis (referred to as riveting column) and other parts, forming the assembly systems of riveting of sheet metal. In addition to the robot, the system also has moving table, clamp, a number of riveting column station and spin riveter etc. Moving table is equipped with the clamp, it can move in the X and Y directions, respectively. The clamp that fixed the sheet metal work-piece can move in Z-direction, which make it easy for assembling the riveting axis into the riveting holes on the work-piece. Robot can move along the Y axis and swing around the Z axis, make the nozzle that is in the end of manipulator move between riveting column stations and spin riveter, which pick up and place the riveting column. A number of riveting column station is used for store riveting column and sorting them. Spin riveter rotates while moving along the Z axis at the same time, by pressure and rotational force it completes the column riveting on sheet metal parts.
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Felis, Józef, Andrzej Zbrowski, Tomasz Giesko, and Jordan Mężyk. "Structure Synthesis and Mechanical Parameters Choice for a Manipulating Mechanism for Acoustical Measurements in Anechoic Chamber." Solid State Phenomena 147-149 (January 2009): 13–18. http://dx.doi.org/10.4028/www.scientific.net/ssp.147-149.13.
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The article presents the structural and geometric synthesis and mechanical parameter choice for a manipulation mechanism for measurement microphone positioning during acoustical tests in anechoic chamber. Usually the aims of acoustical measurements in anechoic chamber are: noise source Sound Power Level estimation, electroacoustical transducer directional characteristics measurement, sound diffusing characteristic of a structure measurement, measurement of Sound Pressure Level on a given measurement grid The specific of that kind of measurements brings up the need of measurement microphone positioning in many points of the measurement space accordingly to relevant standards. In most cases during the tests it is necessary to position the microphone in certain points on the hemisphere. In such cases utilizing of typical microphone stands impedes the measurement and extends the time needed for the tests. Those circumstances led to idea of measurement manipulator construction that would allow changing the microphone position during the measurement accordingly to a specified algorithm. The following assumptions for construction were taken: measurement microphone moves on the hemisphere with a maximal radius of 2 m, the weight of transported object (microphone or other) does not exceed 1 kg, positioning accuracy is 1 mm. Structural and geometric synthesis was made taking into account mounting conditions in anechoic chamber in Department of Mechanics and Vibroacoustics AGH-UST. There were several variants labored that fulfilled the assumptions. The choice of particular solution was made based on: • manipulator drives possible installation analysis with regard to their acoustical noise emission • structure stiffness analysis with regard to assumed positioning accuracy of the microphone Finally a modular construction of manipulator was chosen, which is composed of industrial turntable (built in the level of the wire netting) and two linear motion modules (long axis, short axis). That solution means that the device under test fixed on the turntable rotates in the range of 2π, and the measurement microphone moves on the track of one quarter of a circle. Specific angular position of the linear modules was chosen which allows minimal dimensions of linear modules. Simultaneously the control structure and the software part are developed. The usefulness of the manipulator will be definitely confirmed by a research that should evaluate the influence of the construction elements on the acoustical free field in an anechoic chamber.
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Zhu, Xiao Rong, Hui Ping Shen, and Wei Zhu. "Realization and Simulation of Motion Trajectory of a 2-DOF Planar Parallel Manipulator." Key Engineering Materials 467-469 (February 2011): 1351–56. http://dx.doi.org/10.4028/www.scientific.net/kem.467-469.1351.
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A kind of 2-DOF parallel manipulator driven by two sliders moving along two parallel guides is analyzed. Based on the explicit expression of inverse position, velocity and acceleration analyses, the mobile trajectory of this manipulator is investigated and simulated. In trajectory planning, the trajectory profiles are assigned to be accelerated and decelerated at the first and last few seconds, respectively, and keep at constant speed for the remainder of time, where the forth-order polynomial is fitted during acceleration and deceleration, and clothoid curve is applied around the corner of axis. Then the mobile rule exerted on the actuator sliders is obtained using inverse position based on the desired end-effecter trajectory. Finally, the virtual prototype of this mechanism is modeled using Solidwork and the kinematics and dynamics simulation is performed using Cosmostion. The result shows that both velocity, acceleration of the sliders and the driving force exerted on the sliders are continuous curves, which can fully satisfy the demand of high-accuracy and real-time processing of the high-speed Manipulator.
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Zhang, Haiqiang, Hairong Fang, Yuefa Fang, and Bingshan Jiang. "Workspace Analysis of a Hybrid Kinematic Machine Tool with High Rotational Applications." Mathematical Problems in Engineering 2018 (June 26, 2018): 1–12. http://dx.doi.org/10.1155/2018/2607497.
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This paper presents a novel parallel manipulator with one translational and two rotational (1T2R) degrees of freedom that can be employed to form a five-degree-of-freedom hybrid kinematic machine tool for large heterogeneous complex structural component machining in aerospace field. Compared with serial or parallel machine, hybrid machine has the merits of high stiffness, high speed, large workspace, and complicated surface processing ability. To increase stiffness, three-degree-of-freedom redundantly actuated and overconstrained 2PRU-PRPS parallel manipulator (P denotes the active prismatic joint) is proposed, which is utilized as the main body of hybrid machine. By resorting to the screw theory, the degree of freedom of the proposed mechanism is briefly addressed including the initial configuration and general configuration and validated by Grübler-Kutzbach (G-K) equation. Next, kinematic inverse solution and parasitic motion of the parallel manipulator are deduced and the transformational relations between the Euler angle and Tilt-Torsion (T-T) angle are identified. Thirdly, the performance evaluation index of orientation workspace is introduced, and the reachable workspace and joint workspace are formulated. Through specific examples, the reachable workspace, task workspace, and joint workspace of the redundant actuation parallel manipulator are depicted. Compared with overstrained 2PRU-PRS parallel manipulator, corresponding analyses illustrate that the proposed parallel manipulator owns much better orientation capability and is very meaningful to the development of the five-axis hybrid machine tool.
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Golubev, Yu F., and E. V. Melkumova. "Transfer by a Manipulator with a Three-finger Grasp of a Brittle Cylinder." Multiphase Systems 14, no. 3 (2019): 202–7. http://dx.doi.org/10.21662/mfs2019.3.026.
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We consider the problem of the brittle cylinder grasping by the n fingers of the robot-manipulator. Each finger contacts the cylinder in a single supporting point with Amontons-Coulomb or for two footholds spinning friction. Using numerical simulations and analytically, possible locations of contact points on the cylinder, for which there is a kinetostatics problem solution when the cylinder is moved by three fingers, are received. By the analogy of the equilibrium of a three-legged robot on a cylinder for the problems of transfer by a manipulator with a three-finger grasp of a cylinder or for a robot on a surface which legs suspension points are on a cylinder surface. Two supporting points can be on one diameter in the cylinder base. Or because of friction on the opposite sides of the robot center of mass or giving in the dynamics, it is point C. The analogy of the problem is oscillations in the vicinity of the stable equilibrium one cylinder on another. The cylinder lies on one finger rectangular to it, of the hand of a hu-manoid robot, adheres to the end of the other finger. Similarly holds the glass. Robot can hold the horizontal cylinder by three fingers. Let one of the points is in vertical plane containing cylinder axis and another are in the plane orthogonal to the axis. The supporting points are on the external surface of the lower semi-cylinder and the cylinder center mass is in the footholds triangle. The supporting set is divided into two subsets.
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Vagaš, Marek. "Automated Assembly of Arc-Extinguish Chamber for Circuit Breaker Elements." Applied Mechanics and Materials 282 (January 2013): 197–202. http://dx.doi.org/10.4028/www.scientific.net/amm.282.197.
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The article discusses about automated workplace design for assembly of arc-extinguish chamber for circuit breaker elements. Arc-extinguish chamber contains of metal part and plastic chamber and serves for extinguishing of electrical arc, which ensue from disconnection of electrical current from electrical circumference (appliance) by overloading or short circuit. Proposed solution automates whole assembly process of arc-extinguish chamber and contains of linear stepper unit, two-axis manipulator and two vibrating trays with automated feeding of metal parts and plastic chambers.
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Shen, Hui Ping, Lei Ding, Chang Yu Xue, Ju Li, Jia Ming Deng, and Shan Shu Liu. "Research on 2-Dof Parallel Robot and its Motion Characteristics." Advanced Materials Research 139-141 (October 2010): 2203–6. http://dx.doi.org/10.4028/www.scientific.net/amr.139-141.2203.
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A novel robot, derived from a planar parallel mechanism, is presented. With two sliders driving on the same side of parallel guide rails, this simple but practical mechanism is capable of realizing a large workspace. The direct and inverse kinematical solutions are given. The simulation demonstrates that all kinds of straight lines and circles can be realized by the end actuator of the robot; the corresponding motion disciplines and characteristics driven by the two sliders are analyzed; the results are verified on the prototype. By allowing the end actuator to move in Z-direction or to rotate around A or B-axis, three-, four-, five-axis manipulator would be composed and surface welding and space cutting would be realized. This paper lays the foundation for the real-time control and industrial application of this novel robot.
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Maruo, Shoji, and Yojiro Hiratsuka. "Optically Driven Micromanipulators with Rotating Arms." Journal of Robotics and Mechatronics 19, no. 5 (October 20, 2007): 565–68. http://dx.doi.org/10.20965/jrm.2007.p0565.
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We propose optically controlled micromanipulation tools that operate in sealed environments. The micromanipulator arm has probes to grasp microobjects and a handle to rotate the arm on its long axis. When a laser beam is focused on the handle and scanned linearly on the focal plane, the handle inclines toward the focus, rotating the arm on its long axis for probes to grasp a microobject. Rotation enable the microobject to be grasped separately from a substrate. Micromanipulators, fabricated by using two-photon microstereolithography, can catch microparticles in three dimensions, and a single manipulator arm with twin probes has been used to slide a microparticle on a glass substrate. Such optically controlled micromanipulators are potentially versatile, powerful tools for micro total analysis in biological applications.
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Akulenko, L., N. Bolotnik, D. Leshchenko, and E. Palii. "ON INERTIAL MOTION OF AN ABSOLUTELY RIGID BODY ON A THREE-DEGREE SUSPENSION WITH LINKS OF FINITE LENGTH." Mechanics And Mathematical Methods 2, no. 2 (December 2020): 6–17. http://dx.doi.org/10.31650/2618-0650-2020-2-2-6-17.
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Papers on the dynamics of an absolutely rigid body with a fixed point generally assume that the mechanical system has three degrees of freedom. This is the situation when the body is attached to a fixed base by a ball-and-socket joint. On engineering systems one often encounters rigid bodies attached to a base by a two-degrees-of-freedom joint, consisting of a fixed axis and a movable one, which are mutually perpendicular. Such systems have two degrees of freedom, but the set of kinematically possible motions is quite rich. Dynamic analysis of the motion of a rigid body with a two-degree hinge in a force field is an integral part of the description of the action of mechanical actions of robotic systems. In recent decades, an increasingly closed role in the dynamics of rigid body systems has been played by manipulation robots consisting of a sequential chain of rigid links and controlled by means of torque drives in articulated joints. The same class of objects can be attributed to many biological systems that imitate, for example, the movements of a person or animal (walking, running, jumping). Two-link systems have a variety of practical applications and an almost equally wide range of areas of theoretical research. We note, in particular, the analysis of free and forced plane-parallel motion of a bundle of two rigid bodies connected by an ideal cylindrical hinge and simulating a composite satellite in outer space, a two-link manipulator, and an element of a crushing machine. The dynamic behavior of a rigid body in the gimbal suspension is a system, which can be interpreted as two-degree manipulator and used an element of more complex robotic structures. The linear mathematical model of two-link manipulator free oscillations with viscous friction in both its joints is a system, which reduces to the calculation scheme of double pendulum and allows the construction of exact analytical solution in the partial case. According to the research methodology, the proposed paper is close to works, where the motion by inertia of a plane two–rigid body hinged system was studied and devoted to the study of the motion of an absolutely rigid body on a power-to-power joint.
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Ding, Bingxiao, Yangmin Li, Xiao Xiao, Yirui Tang, and Bin Li. "Design and analysis of a 3-DOF planar micromanipulation stage with large rotational displacement for micromanipulation system." Mechanical Sciences 8, no. 1 (May 23, 2017): 117–26. http://dx.doi.org/10.5194/ms-8-117-2017.
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Abstract. Flexure-based mechanisms have been widely used for scanning tunneling microscopy, nanoimprint lithography, fast servo tool system and micro/nano manipulation. In this paper, a novel planar micromanipulation stage with large rotational displacement is proposed. The designed monolithic manipulator has three degrees of freedom (DOF), i.e. two translations along the X and Y axes and one rotation around Z axis. In order to get a large workspace, the lever mechanism is adopted to magnify the stroke of the piezoelectric actuators and also the leaf beam flexure is utilized due to its large rotational scope. Different from conventional pre-tightening mechanism, a modified pre-tightening mechanism, which is less harmful to the stacked actuators, is proposed in this paper. Taking the circular flexure hinges and leaf beam flexures hinges as revolute joints, the forward kinematics and inverse kinematics models of this stage are derived. The workspace of the micromanipulator is finally obtained, which is based on the derived kinematic models.
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Nobili, A., A. Strozzi, and P. Vaccari. "Exact deflection expressions for a thin solid circular plate loaded by periphery couples." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 215, no. 3 (March 1, 2001): 341–51. http://dx.doi.org/10.1243/0954406011520751.
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A mechanical analysis is carried out for a thin, solid, circular plate, deflected by a series of periphery-concentrated couples with a radial or circumferential axis. Although such couples need not be of equal intensity or angularly equispaced, they must constitute a self-equilibrated system of couples. This problem is decomposed into a combination of two basic models, the first of which considers a single periphery couple with a radial axis, and the second addresses an edge couple with a circumferential axis. In both models the concentrated border couple is equilibrated by a sinusoidal boundary line load of proper intensity, whose wavelength equals the plate edge. When such basic configurations are combined, respecting the condition that the system of concentrated couples be self-equilibrated, the effects of the sinusoidal loads cancel out, and the title problem is recovered. A classical series solution in terms of purely flexural plate deflections is achieved for the two basic models, where the series coefficients are computed with the aid of an algebraic manipulator. For both models, the series is summed in analytical form over the whole plate region. Closed-form deflection formulae can thus be easily derived from the two basic models for any combination of self-equilibrated edge couples, where some selected relevant situations are developed in detail.
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Wong, Ching-Chang, Li-Yu Yeh, Chih-Cheng Liu, Chi-Yi Tsai, and Hisasuki Aoyama. "Manipulation Planning for Object Re-Orientation Based on Semantic Segmentation Keypoint Detection." Sensors 21, no. 7 (March 24, 2021): 2280. http://dx.doi.org/10.3390/s21072280.
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In this paper, a manipulation planning method for object re-orientation based on semantic segmentation keypoint detection is proposed for robot manipulator which is able to detect and re-orientate the randomly placed objects to a specified position and pose. There are two main parts: (1) 3D keypoint detection system; and (2) manipulation planning system for object re-orientation. In the 3D keypoint detection system, an RGB-D camera is used to obtain the information of the environment and can generate 3D keypoints of the target object as inputs to represent its corresponding position and pose. This process simplifies the 3D model representation so that the manipulation planning for object re-orientation can be executed in a category-level manner by adding various training data of the object in the training phase. In addition, 3D suction points in both the object’s current and expected poses are also generated as the inputs of the next operation stage. During the next stage, Mask Region-Convolutional Neural Network (Mask R-CNN) algorithm is used for preliminary object detection and object image. The highest confidence index image is selected as the input of the semantic segmentation system in order to classify each pixel in the picture for the corresponding pack unit of the object. In addition, after using a convolutional neural network for semantic segmentation, the Conditional Random Fields (CRFs) method is used to perform several iterations to obtain a more accurate result of object recognition. When the target object is segmented into the pack units of image process, the center position of each pack unit can be obtained. Then, a normal vector of each pack unit’s center points is generated by the depth image information and pose of the object, which can be obtained by connecting the center points of each pack unit. In the manipulation planning system for object re-orientation, the pose of the object and the normal vector of each pack unit are first converted into the working coordinate system of the robot manipulator. Then, according to the current and expected pose of the object, the spherical linear interpolation (Slerp) algorithm is used to generate a series of movements in the workspace for object re-orientation on the robot manipulator. In addition, the pose of the object is adjusted on the z-axis of the object’s geodetic coordinate system based on the image features on the surface of the object, so that the pose of the placed object can approach the desired pose. Finally, a robot manipulator and a vacuum suction cup made by the laboratory are used to verify that the proposed system can indeed complete the planned task of object re-orientation.
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Fenili, André. "The Rigid-Flexible Two Link Manipulator with Joint Friction and Different Number of Modes for the Flexible Link Discretization." Applied Mechanics and Materials 706 (December 2014): 222–32. http://dx.doi.org/10.4028/www.scientific.net/amm.706.222.
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A Rigid-Flexibletwo Link Rotatingmanipulator Likesystem is Mathematically Modeled Usinglagrange’s Equations. Two Different Approaches are Considered for the Flexible Linkdiscretization:(a) only the First Flexuralmode is Considered and (b) Two Flexural Modes are Considered. the Mainidea here is to Investigate the Participation of the Second Flexural Mode in the System Dynamics Forslow and Fast Maneuversin the Presence of Friction Forces. Nonlinearity Arises in this Problem Fromthe Coupling between the Variable Representing the Angular Velocity of the Rotating Axis Connected Tothe Flexible Link and the Variable Representing the Vibration of the Flexible Link. Sufficiently Largeangular Velocities are Considered in Order to the System to Undergo Sufficiently Strongnonlinearbehavior.Coulomb Friction Isconsidered on both Joints.For Position/velocity of both Rotating Axesand Elimination of Vibration in the Flexible Link the Nonlinear Control Technique Named Statedependent Riccati Equation (SDRE) is Applied. Theresults for the Different Mathematicaldescriptions of the System are Compared and Discussed
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Zhu, Xiao Rong, Yi Lu, and Hui Ping Shen. "Kinematic Analysis of a Planar Mechanism Driven by Two Orthogonal Layout Actuators." Advanced Materials Research 490-495 (March 2012): 2305–9. http://dx.doi.org/10.4028/www.scientific.net/amr.490-495.2305.
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In this paper, a planar five-bar mechanism driven by two orthogonal layout actuators is proposed. The inverse and forward kinematics can be described in closed form. The Jacobi matrix, singularity and workspace of the mechanism are investigated. In addition, charts of some performance indices, such as dexterity, velocity, payload capability and stiffness index, are plotted. The results show that the mechanism has a flatter singularity-free workspace, which is usually our research object. On the other hand, Dexterity, Payload capability and stiffness index of the mechanism are basically the same distribution on the workspace, which are axis symmetric. But, the trend of velocity index is opposite. The proposed mechanism can be applied to the field of machine tools or used as the mobile base for a spatial manipulator. The results of the paper are very useful for the design and application of the new mechanism
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Samborski, Tomasz, Jan Wiejak, and Eugeniusz Matras. "Device for Low-Cost Assembly of Chips in RFID Inlays." Solid State Phenomena 237 (August 2015): 239–44. http://dx.doi.org/10.4028/www.scientific.net/ssp.237.239.
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Security systems employ the RFID method to protect objects and data and to ensure public safety and the safety of commercial activity, e.g. through the control over technological processes. The research activity aimed at improving the level of safety of electronic and technical protection needs to be verified through the manufacture of prototype IDs with RFID inlays.The authors presents an original experimental device enabling the implementation of individual chips in RFID inlays, which were made on a flexible base to which an RFID antenna is attached. The collection of the chip from the dispenser and an unambiguous orientation of the soldered tips in relation to the antenna are provided by a four-axis vacuum manipulator cooperating with a vision system identifying the location of the chip on the manipulator and its final application area. A computer control system enables the operation in two modes, i.e. a semi-automatic mode in which it is possible to manually control the order and the way in which individual tasks are performed, and an automatic mode conducted according to the designed algorithm. The developed device is intended for research on the ways to improve the manufacturing techniques and electronic document protection by means of RFID technologies.
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Jia, Jidong, Minglu Zhang, Xizhe Zang, He Zhang, and Jie Zhao. "Dynamic Parameter Identification for a Manipulator with Joint Torque Sensors Based on an Improved Experimental Design." Sensors 19, no. 10 (May 15, 2019): 2248. http://dx.doi.org/10.3390/s19102248.
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As the foundation of model control, robot dynamics is crucial. However, a robot is a complex multi-input–multi-output system. System noise seriously affects parameter identification results, thereby inevitably requiring us to conduct signal processing to extract useful signals from chaotic noise. In this research, the dynamic parameters were identified on the basis of the proposed multi-criteria embedded optimization design method, to obtain the optimal excitation signal and then use maximum likelihood estimation for parameter identification. Considering the movement coupling characteristics of the multi-axis, experiments were based on a two degrees-of-freedom manipulator with joint torque sensors. Simulation and experimental results showed that the proposed method can reasonably resolve the problem of mutual opposition within a single criterion and improve the identification robustness in comparison with other optimization criteria. The mean relative standard deviation was 0.04 and 0.3 lower in the identified parameters than in F1 and F3, respectively, thus signifying that noise is effectively alleviated. In addition, validation experimental curves were close to the estimation model, and the average of root mean square (RMS) is 0.038, thereby confirming the accuracy of the proposed method.
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Carabin, Giovanni, and Lorenzo Scalera. "On the Trajectory Planning for Energy Efficiency in Industrial Robotic Systems †." Robotics 9, no. 4 (October 26, 2020): 89. http://dx.doi.org/10.3390/robotics9040089.
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In this paper, we present an approach for the minimum-energy trajectory planning in industrial robotic systems. The method is based on the dynamic and electro-mechanical modeling of one-degree-of-freedom systems and the derivation of the energy formulation for standard point-to-point trajectories, as, for instance, trapezoidal and cycloidal speed profiles. The proposed approach is experimentally validated on two robotic systems, namely a linear axis of a Cartesian manipulator built in the 1990’s, and a test bench composed of two servomotors directly connected or coupled by means of a planetary gear. During the tests, the electrical power expended by the systems is measured and integrated over time to compute the energy consumption for each trajectory. Despite the limitations of the energy measurement systems, the results reveal a trend in agreement with the theoretical calculations, showing the possibility of applying the method for enhancing the performance of industrial robotic systems in terms of energy consumption in point-to-point motions.
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Hijazi, Anas, Jean-François Brethé, and Dimitri Lefebvre. "Design of an XY-theta platform held by a planar manipulator with four revolute joints and evaluation of its precision performances." Robotica 34, no. 11 (April 8, 2015): 2532–45. http://dx.doi.org/10.1017/s0263574715000193.
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SUMMARYThis paper is about the precision performance evaluation of an XY-theta platform, with a patented kinematic design. Indeed, this platform is held by a serial redundant robot arm actuated with four revolute joints. The platform offers a wide 300 × 300 mm workspace, whereas the whole mechanism is extremely compact. Any workpiece on the platform can be positioned under a vertical axis to be grasped or manufactured in a two-step approach: in a coarse positioning mode, the four revolute joints are controlled to position and orientate the workpiece with a position error of less than 10 μm; in a fine positioning mode, two revolute joints are mechanically blocked while two others are controlled to reduce the final error to below 2 μm. The mechanism design and the choice of the blocked and moving joints are optimized to enhance the positioning performances in the two-step positioning method. In this paper, the platform positioning repeatability and its spatial resolution are characterized with the help of a camera. The advantage of this method is that it avoids any mechanical contact and can be implemented easily. Then, these results are compared to our previous precision performance evaluation obtained with the stationary cube method. Finally, the positioning repeatability is estimated at 6.5 μm in the coarse positioning mode and 1.4 μm in the fine positioning mode. Between the coarse and fine mode, the repeatability is thus improved by the factor of four, as predicted by the theory.
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Sun, Jingyu, Yanjun Liu, and Chen Ji. "Improved singular robust inverse solutions of redundant serial manipulators." International Journal of Advanced Robotic Systems 17, no. 3 (May 1, 2020): 172988142093204. http://dx.doi.org/10.1177/1729881420932046.
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To address the Jacobian matrix approximation error, which usually exists in the iterative solving process of the classic singular robust inverse method, the correction coefficient α is introduced, and the improved singular robust inverse method is the result. On this basis, the constant improved singular robust method and the intelligent improved singular robust inverse method are proposed. In addition, a new scheme, combining particle swarm optimization and artificial neural network training, is applied to obtain real-time parameters. The stability of the proposed methods is verified according to the Lyapunov stability criteria, and the effectiveness is verified in the application examples of spatial linear and curve trajectories with a seven-axis manipulator. The simulation results show that the improved singular robust inverse method has better optimization performance and stability. In the allowable range, the terminal error is smallest, and there is no lasting oscillation or large amplitude. The least singular value is largest, and the joint angular velocity is smallest, exactly as expected. The derivative of the Lyapunov function is negative definite. Comparing the two extended methods, the constant improved singular robust method performs better in terms of joint angular velocity and least singular value optimization, and the intelligent improved singular robust inverse method can achieve a smaller terminal error. There is little difference between their overall optimization effects. However, the adaptability of the real-time parameters makes the intelligent improved singular robust inverse method the first choice for kinematic control of redundant serial manipulators.
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Fujie, Hiromichi, Takeshi Sekito, and Akiyuki Orita. "A Novel Robotic System for Joint Biomechanical Tests: Application to the Human Knee Joint." Journal of Biomechanical Engineering 126, no. 1 (February 1, 2004): 54–61. http://dx.doi.org/10.1115/1.1644567.
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The objectives of the work reported in this article were to develop a novel 6-degree-of-freedom (DOF) robotic system for knee joint biomechanics, to complete a hybrid force-position control scheme, to evaluate the system performance, and to demonstrate a combined loading test. The manipulator of the system utilizes two mechanisms; the upper mechanism has two translational axes and three rotational axes while the lower mechanism has only a single translational axis. All axes were driven with AC servo-motors. This unique configuration results in a simple kinematic description of manipulator motion. Jacobian transformation was used to calculate both the displacement and force/moment, which allowed for a hybrid control of the displacement of, and force/moment applied to, the human knee joint. The control and data acquisition were performed on a personal computer in the C-language programming environment with a multi-tasking operating system. Preliminary tests revealed that the clamp-to-clamp compliance of the system was smaller in the vertical (Z) and longitudinal (Y) directions (0.001 mm/N) than in lateral (X) direction (0.003 mm/N). The displacement error under the application of 500 N of load was smallest in the vertical direction (0.001±0.003 mm (mean±SD), and largest in the lateral direction (0.084±0.027 mm). Using this test system, it was possible to simulate multiple loading conditions in a human knee joint in which a cyclic anterior force was applied together with a coupled, joint compressive force, while allowing natural knee motion. The developed system seems to be a useful tool for studies of knee joint biomechanics.
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Uzunoglu, Emre, Mehmet Ismet Can Dede, and Gökhan Kiper. "Trajectory planning for a planar macro-micro manipulator of a laser-cutting machine." Industrial Robot: An International Journal 43, no. 5 (August 15, 2016): 513–23. http://dx.doi.org/10.1108/ir-02-2016-0057.
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Purpose In the industry, there is always a demand to shorten the task completion durations to maximize the efficiency of the operation. This work focuses on making use of a special type of kinematic redundancy, macro–micro manipulation, to minimize the task completion duration. The purpose of this paper is to develop the most convenient trajectory planner to be integrated with industrial computerized numerical control (CNC) systems to resolve kinematic redundancy for task duration minimization. Design/methodology/approach A special type of kinematic redundancy is devised by using two kinematically different mechanisms that have different advantages, which are named as macro and micro mechanisms. In this case, the control design including the trajectory planning should be devised taking into account the distinct advantages of both mechanisms. A new trajectory planning algorithm is designed and used for the constructed planar laser-cutting machine, and some benchmark pieces are cut. Findings Offline method has practical limitations for employment in a real case scenario such as assuming infinite jerk limits for each axis motion. This limitation was removed by using an online trajectory generation technique. Experimental test results indicate that the online trajectory planning technique developed for the macro–micro mechanism to shorten the task duration was successful. Practical implications Although the new trajectory planning algorithm is implemented for a laser-cutting machine, it can also be used for other manufacturing systems that require higher acceleration and accuracy levels than the conventional machines. The new algorithm is compatible with the commercially available CNC systems. Originality/value In this work, a new approach to reducing the task duration for planar machining operations was introduced by making use of macro–micro manipulation concept. The core novelty of the work is devising trajectory planning algorithms to get the most efficiency in terms of acceleration limits from a macro–micro manipulation while making these algorithms deployable to most of the CNC systems.
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Fujiwara, Hidenori, Sho Naimen, Atsushi Higashiya, Yuina Kanai, Hiroshi Yomosa, Kohei Yamagami, Takayuki Kiss, et al. "Polarized hard X-ray photoemission system with micro-positioning technique for probing ground-state symmetry of strongly correlated materials." Journal of Synchrotron Radiation 23, no. 3 (April 1, 2016): 735–42. http://dx.doi.org/10.1107/s1600577516003003.
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An angle-resolved linearly polarized hard X-ray photoemission spectroscopy (HAXPES) system has been developed to study the ground-state symmetry of strongly correlated materials. The linear polarization of the incoming X-ray beam is switched by a transmission-type phase retarder composed of two diamond (100) crystals. The best value of the degree of linear polarization was found to be −0.96, containing a vertical polarization component of 98%. A newly developed low-temperature two-axis manipulator enables easy polar and azimuthal rotations to select the detection direction of photoelectrons. The lowest temperature achieved was 9 K, offering the chance to access the ground state even for strongly correlated electron systems in cubic symmetry. A co-axial sample monitoring system with long-working-distance microscope enables the same region on the sample surface to be measured before and after rotation. Combining this sample monitoring system with a micro-focused X-ray beam by means of an ellipsoidal Kirkpatrick–Baez mirror (25 µm × 25 µm FWHM), polarized valence-band HAXPES has been performed on NiO for voltage application as resistive random access memory to demonstrate the micro-positioning technique and polarization switching.
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Ma, Yanqin, Kai Du, Dongfeng Zhou, Juan Zhang, Xilong Liu, and De Xu. "Automatic precision robot assembly system with microscopic vision and force sensor." International Journal of Advanced Robotic Systems 16, no. 3 (May 1, 2019): 172988141985161. http://dx.doi.org/10.1177/1729881419851619.
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An automatic precision robot assembly system is established. The robot assembly system mainly consists of an industrial robot, three cameras, a micro force sensor, and a specific gripper. The industrial robot is a six-axis serial manipulator, which is used to conduct grasping and assembly subtasks. Two microscopic cameras are fixed on two high accuracy translational platforms to provide visual information in aligning stage for assembly. While one conventional camera is installed on the robotic end effector to guide the gripper to grasp component. The micro force sensor is installed on the robotic end effector to perceive the contacted forces in inserting stage. According to the characteristics of components, an adsorptive gripper is designed to pick up components. In addition, a three-stage “aligning–approaching–grasping” control strategy for grasping subtask and a two-stage “aligning–inserting” control strategy for assembly subtask are proposed. Position offset compensation is computed and introduced into aligning stage for assembly to make the grasped component in the microscopic cameras’ small field of view. Finally, based on the established robot assembly system and the proposed control strategies, the assembly tasks including grasping and assembly are carried out automatically. With 30 grasping experiments, the success rate is 100%. Besides, the position and orientation alignment errors of pose alignment for assembly are less than 20 μm and 0.1°.
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KELMANSON, MARK A. "On inertial effects in the Moffatt–Pukhnachov coating-flow problem." Journal of Fluid Mechanics 633 (August 25, 2009): 327–53. http://dx.doi.org/10.1017/s0022112009006703.
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The effects are investigated of including inertial terms, in both small- and large-surface-tension limits, in a remodelling of the influential and fundamental problem first formulated by Moffatt and Pukhnachov in 1977: that of viscous thin-film free-surface Stokes flow exterior to a circular cylinder rotating about its horizontal axis in a vertical gravitational field.An analysis of the non-dimensionalizations of previous related literature is made and the precise manner in which different rescalings lead to the asymptotic promotion or demotion of pure-inertial flux terms over gravitational-inertial terms is highlighted. An asymptotic mass-conserving evolution equation for a perturbed-film thickness is derived and solved using two-timescale asymptotics with a strained fast timescale. By using an algebraic manipulator to automate the asymptotics to high orders in the small expansion parameter of the ratio of the film thickness to the cylinder radius, consistent a posteriori truncations are obtained.Via two-timescale and numerical solutions of the evolution equation, new light is shed on diverse effects of inertia in both small- and large-surface-tension limits, in each of which a critical Reynolds number is discovered above which the thin-film evolution equation has no steady-state solution due to the strength of the destabilizing inertial centrifugal force. Extensions of the theory to the treatment of thicker films are discussed.
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Bingol, Mustafa Can, and Omur Aydogmus. "Practical application of a safe human-robot interaction software." Industrial Robot: the international journal of robotics research and application 47, no. 3 (January 16, 2020): 359–68. http://dx.doi.org/10.1108/ir-09-2019-0180.
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Purpose Because of the increased use of robots in the industry, it has become inevitable for humans and robots to be able to work together. Therefore, human security has become the primary noncompromising factor of joint human and robot operations. For this reason, the purpose of this study was to develop a safe human-robot interaction software based on vision and touch. Design/methodology/approach The software consists of three modules. Firstly, the vision module has two tasks: to determine whether there is a human presence and to measure the distance between the robot and the human within the robot’s working space using convolutional neural networks (CNNs) and depth sensors. Secondly, the touch detection module perceives whether or not a human physically touches the robot within the same work environment using robot axis torques, wavelet packet decomposition algorithm and CNN. Lastly, the robot’s operating speed is adjusted according to hazard levels came from vision and touch module using the robot’s control module. Findings The developed software was tested with an industrial robot manipulator and successful results were obtained with minimal error. Practical implications The success of the developed algorithm was demonstrated in the current study and the algorithm can be used in other industrial robots for safety. Originality/value In this study, a new and practical safety algorithm is proposed and the health of people working with industrial robots is guaranteed.
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Ouyang, Zhihua, Wenjun Wang, Nicholas Vaudreuil, Robert Tisherman, Yiguo Yan, Patrick Bosch, James Kang, and Kevin Bell. "Biomechanical Analysis of a Growing Rod with Sliding Pedicle Screw System for Early-Onset Scoliosis." Journal of Healthcare Engineering 2019 (June 12, 2019): 1–7. http://dx.doi.org/10.1155/2019/9535070.
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Early-onset scoliosis (EOS) remains a challenging condition for which current nonfusion surgeries require iterative lengthening surgeries. A growing rod with sliding pedicle screw system (GRSPSS) was developed to treat spinal deformities without repeated operative lengthening. This study was performed to evaluate whether GRSPSS had similar stability as a conventional pedicle screw system to maintain deformity correction. A serial-linkage robotic manipulator with a six-axis load cell positioned on the end-effector was utilized to evaluate the mechanical stability of the GRSPSS versus conventional fixed scoliosis instrumentation. Ten skeletally mature thoracic female Katahdin sheep spines (T4-L1) were subjected to 2.5 Nm of flexion-extension (FE), lateral bending (LB), and axial rotation (AR) in 2° increments for each state. The overall range of motion (ROM), apical segment ROM, and stiffness were calculated and reported. A two-tailed paired t-test was used to detect significant differences (p<0.05) between the fixed group and GRSPSS fixation. There were no significant differences in overall range of motion (ROM), apical segment ROM, or stiffness for FE or LB between the GRSPSS group and fixed group. In AR, the GRSPSS group showed increased ROM compared to the fixed group for the overall spine (36.0° versus 19.2°, p<0.01) and for the instrumented T8-T10 segments (7.0° versus 2.9°, p=0.02). Similarly, the fixed rod elastic zone (EZ) stiffness was significantly greater than the GRSPSS EZ stiffness (0.29 N/m versus 0.17 N/m, p<0.001). The space around the rod allows for the increased AR observed with the GRSPSS fusion technique and is necessary for axial growth. The GRSPSS fusion model shows equivalent flexion and LB stability to current fusion models and represents a stable fusion technique and may allow for longitudinal growth during childhood.
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Angeles, Jorge. "The Qualitative Synthesis of Parallel Manipulators." Journal of Mechanical Design 126, no. 4 (July 1, 2004): 617–24. http://dx.doi.org/10.1115/1.1667955.
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As shown in this paper, when designing parallel manipulators for tasks involving less than six degrees of freedom, the topology can be laid out by resorting to qualitative reasoning. More specifically, the paper focuses on cases whereby the manipulation tasks pertain to displacements with the algebraic structure of a group. Besides the well-known planar and spherical displacements, this is the case of displacements involving: rotation about a given axis and translation in the direction of the same axis (cylindrical subgroup); translation in two and three dimensions (two- and three-dimensional translation subgroups); three independent translations and rotation about an axis of fixed direction, what is known as the Scho¨nflies subgroup; and similar to the Scho¨nflies subgroup, but with the rotation and the translation in the direction of the axis of rotation replaced by a screw displacement. For completeness, the fundamental concepts of motion representation and groups of displacements, as pertaining to rigid bodies, are first recalled. Finally, the concept of Π-joint, introduced elsewhere, is generalized to two and three degrees of freedom, thereby ending up with the Π2-and the Π3-joints, respectively.
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Zhou, Chao, Lu Deng, Long Cheng, Zhiqiang Cao, Shuo Wang, and Min Tan. "Automated Axis Alignment for a Nanomanipulator inside SEM and Its Error Optimization." Scanning 2017 (2017): 1–8. http://dx.doi.org/10.1155/2017/3982503.
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In the motion of probing nanostructures, repeating position and movement is frequently happing and tolerance for position error is stringent. The consistency between the axis of manipulators and image is very significant since the visual servo is the most important tool in the automated manipulation. This paper proposed an automated axis alignment method for a nanomanipulator inside the SEM by recognizing the position of a closed-loop controlling the end-effector, which can characterize the relationship of these two axes, and then the rotation matrix can be calculated accordingly. The error of this method and its transfer function are also calculated to compare the iteration method and average method. The method in this paper can accelerate the process of axis alignment to avoid the electron beam induced deposition effect on the end tips. Experiment demonstration shows that it can achieve a 0.1-degree precision in 90 seconds.
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Lai, Jim Z., and C. H. Menq. "Motion Control of Manipulators with Closed-Form Inverse Solutions Near Wrist Singularities." Journal of Engineering for Industry 111, no. 1 (February 1, 1989): 87–93. http://dx.doi.org/10.1115/1.3188737.
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Two algorithms, the degenerate axis and iterative methods, are developed for the motion control of manipulators with closed-form solutions in the neighborhood of singularities. These two methods theoretically guarantee a robot’s position accuracy. The degenerate axis method may not work well when a robot’s orientation and location increments become finite. If a robot is moving with slow speed or the interpolation time is in the order of microsecond, the location and orientation increments are small. In this case, the degenerate axis method is favored for it has less computation than that of the iterative method. Two examples are given to illustrate the concepts presented in this paper. Although it cannot be proved that the iterative scheme gives the required position accuracy and minimizes the orientation error, the results seem to show that this scheme converges to an acceptable solution. It is believed that the iterative method is the first of its kind to solve the singular motion control problem by using a robot’s closed-form inverse kinematics. Simple computation for the iterative scheme makes it possible to be implemented in many industrial robots.