Optimal Wrist Design of Wrist-hollow Type 6-axis Articulated Robot using Genetic Algorithm

Hyeon Min Jo(조현민),Won Jee Chung(정원지),Seung Min Bae(배승민),Jong Kap Choi(최종갑),Dae Young Kim(김대영),Yeon Joo Ahn(안연주),Hee Sung Ahn(안희성) 한국기계가공학회 2019 한국기계가공학회지 Vol.18 No.1

In arc-welding applying to the present automobile part manufacturing process, a wrist-hollow type arc welding robot can shorten the welding cycle time, because feedability of a welding wire is not affected by a robot posture and thus facilitates high-quality arc welding, based on stable feeding with no entanglement. In this paper, we will propose the optimization of wrist design for a wrist-hollow type 6-Axis articulated robot. Specifically, we will perform the investigation on the optimized design of inner diameter of hollow arms (Axis 4 and Axis 6) and width of the upper arm by using the simulation of robot motion characteristics, using a Genetic Algorithm (i.e., GA). Our simulations are based on SolidWorks<SUP>®</SUP> for robot modeling, MATLAB<SUP>®</SUP> for GA optimization, and RecurDyn<SUP>®</SUP> for analyzing dynamic characteristics of a robot. Especially RecurDyn<SUP>®</SUP> is incorporated in the GA module of MATLAB<SUP>®</SUP> for the optimization process. The results of the simulations will be verified by using RecurDyn<SUP>®</SUP> to show that the driving torque of each axis of the writs-hollow 6-axis robot with the optimized wrist design should be smaller than the rated output torque of each joint servomotor. Our paper will be a guide for improving the wrist-hollow design by optimizing the wrist shape at a detail design stage when the driving torque of each joint for the wrist-hollow 6-axis robot (to being developed) is not matched with the servomotor specifications.

Development of a 6-axis robot's finger force/moment sensor for stable grasping of an unknown object

Gab-Soon Kim 한국정밀공학회 2004 International Journal of Precision Engineering and Vol.5 No.3

This paper describes the development of a 6-axis robot's finger force/moment sensor, which measures forces Fx (x-direction force), Fy and Fz, and moments Mx (x-direction moment), My and Mz simultaneously, for stable grasping of an unknown object. In order to safely grasp an unknown object using the robot's gripper, the force in the gripping direction and the force in the gravity direction should be measured, and the force control should be performed using the measured forces. Also, the moments Mx, My and Mz to accurately perceive the position of the object in the grippers should be detected. Thus, the robot's gripper should be composed of 6-axis robot's finger force/moment sensor that can measure forces Fx, Fy and Fz, and moments Mx, My and Mz simultaneously. In this paper, the 6-axis robot's finger force/moment sensor for measuring forces Fx, Fy and Fz, and moments Mx, My and Mz simultaneously was newly modeled using several parallel-plate beams, designed, and fabricated. The characteristic test of the fabricated sensor was performed, and the result shows that interference errors of the developed sensor are less than 3%. Also, Robot's gripper with the 6-axis robot's finger force/moment sensor for the characteristic test of force control was manufactured, and the characteristic test for grasping an unknown object using the sensors was performed using it. The fabricated gripper could grasp an unknown object stably. Thus, the developed 6-axis robot's finger force/moment sensor can be used for robot's gripper.

MATLAB<SUP>Ⓡ</SUP>과 Recurdyn<SUP>Ⓡ</SUP>의 Simulink를 활용한 2축 부가 축과 6축 수직 다관절로봇의 기구적 연동에 관한 연구

배승민(Seung-Min Bae),정원지(Won-Jee Chung),노성훈(Seong-Hoon Noh) 한국기계가공학회 2021 한국기계가공학회지 Vol.20 No.4

Currently, 6-axis articulated robots are used throughout the industry because of their 6-dof (degrees of freedom) and usability. However, 6-axis articulated robots have a fixed base and their movements are limited by the rotational operating range of each axis. If the angle of the 2-axis additional axes can be adjusted according to the position and orientation of the end-effector of the 6-axis articulated robot, the effectiveness of the 6-axis articulated robot can be further increased in areas where the angle is important, such as welding. Therefore, in this paper, we proposed a cooperative kinematic inter-operation strategy. The strategy will be verified using the Simulink of MATLAB<SUP>Ⓡ</SUP>, an engineering program, and Recurdyn<SUP>Ⓡ</SUP>, a dynamic simulation program.

로봇의 지능형 발을 위한 6축 발목 힘/모멘트센서

김갑순(Gab-Soon Kim),김천곤(Cheon-Kon Kim),신희준(Hyi-Jun Shin),김현민(Hyeon-Min Kim),윤정원(Jungwon Yoon) 대한기계학회 2006 대한기계학회 춘추학술대회 Vol.2006 No.11

This paper describes the development of 6-axis ankle force/moment sensor for an intelligent foot a humanoid robot. In order to safely walk on uneven terrain in humanoid robot’s walking, the foot should perceive the applied forces Fx, Fy, Fz and moments Mx, My, Mz to itself. The applied forces and moments should be measured from a 6-axis force/moment sensor attached to a humanoid robot’s foot (ankle). They in the published paper already have some disadvantage in the size of the sensor, the rated output and so on. The rated output of each component sensor (6-axis ankle force/moment sensor) is very important to design the 6-axis force/moment sensor for precision measurement. Therefore, each sensor should be designed to be gotten similar the rated output under each rated load. In this paper, the structure of a 6-axis ankle force/moment sensor “which has the rectangular beams for the lots of design variables and the proper size for mounting to robot’s ankle” was modeled and manufactured for a humanoid robot’s foot newly. And, the characteristic test of the developed sensor was carried out. The rated outputs from the derived equations agree well with the results from the experiments. The interference error of the sensor is less than 2.94%.

RecurDyn<SUP>®</SUP>과 LabVIEW<SUP>®</SUP>기반 6축 수직 다관절로봇을 이용한 용접의 효율을 높이는 부가 축의 접목에 대한 연구

홍준락(Jun Rak Hong),정원지(Won Jee Chung),박승규(Seung Kyu Park),노성훈(Seong Hoon Noh) 대한기계학회 2017 대한기계학회 춘추학술대회 Vol.2017 No.11

This paper aims to realize 2-axis additional axes, which increases processing efficiency of a robot by controlling in harmful environments or design fields beyond human reach. Ultimately, this is to create temporal and efficient profits in industrial processing sites including welding and assembling 6-axis articulated robot (RS2). Also, using RecurDyn<SUP>Ⓡ</SUP>, a simulation-based technique is applied. And the motion paths of the welding rod will be compared for two cases in order to verify the necessity of the 2-axis additional axes: 1) when there are no 2-axis additional axes and 2) when there are 2- axis additional axes during welding using the RS2. For this purpose, the angle variations of RS2 axes required for a simulation are compared, on the assumption that each of the four points of the welding bed installed in the 2-axis additional axes of the welding rod in SolidWorks<SUP>Ⓡ</SUP> is point-welded. Then an actual 2-axis additional axes equipment will be grafted on to RS2 and the process times depending on the existence of 2-axis additional axes are compared using a PC-based robot control program, LabVIEW<SUP>Ⓡ</SUP>. The comparison will imply that grafting a 2-axis additional axes equipment on to a 6-axis articulated robot make it possible to control a robot easily, to decrease the process route and the process time drastically, and to maximize robot efficiency.

2축 부가 축을 이용한 6축 수직 다관절로봇의 용접공정 효율 증대를 위한 연구

홍준락(Jun-Rak Hong),조현민(Hyeon-Min Jo),정원지(Won-Jee Chung),박승규(Seung-Kyu Park),노성훈(Seong-Hoon Noh) 한국기계가공학회 2017 한국기계가공학회지 Vol.16 No.6

This paper aims to realize additional axes, which increase the processing efficiency of a robot by controlling in harmful environments. Ultimately, this is to create time and energy savings in industrial sites with 6-axis articulated welding robots (RS2). Using RecurDyn<SUP>Ⓡ</SUP>, a simulation technique is applied. The motion paths of the welding rod are compared for two cases in order to verify the necessity of the additional axes: 1) when there are no additional axes and 2) when there are additional axes during welding using the RS2. For this purpose, the angle variations of the RS2 axes required for the simulation are compared, on the assumption that each of the four points of the welding bed installed on the additional axes of the welding rod in Solidworks<SUP>Ⓡ</SUP> is point-welded. Then, actual additional axes equipment is grafted on to the RS2 and the process times compared using LabVIEW<SUP>Ⓡ</SUP>.

Development of Collaborative Work System using 6-axis Robot

( Byeong-ro Min ),( Duck-ki Kim ),( Se-bu Oh ),( Se-hoon Oh ) 한국농업기계학회 2018 한국농업기계학회 학술발표논문집 Vol.23 No.1

In order to improve the work environment at the agriculture production line, robots are increasing rapidly. Robots are also introducing in order to have consistent quality. Especially when flexible cooperation is required, 6-axis multi-joint robot is applied to the agriculture production line. The purpose of this study is to apply 6 - axis robot to collaborative work. The six-axis robot can modify the shape of the end effector according to the shape of the handling material. We analyzed the interference on links and joints using CATIA Modeling to apply to collaborative work. Through the collaboration robot, the products using CNC machining were measured through the measurement unit device. We have implemented smart factory of processing-quality-history management by configuring the history of processed material through automatic measuring unit device and laser processor. Experiments with 6-axis joint robots were carried out by laser beam machining centered on the reference point and passed after the tolerance within ± 0.1 mm. As a result of 100 measurements, the average error was 0.02 mm. Therefore, we implemented the automation through collaborative work through 6 axis robot design.

Development of a 6-axis robot′s finger force/moment sensor for stable grasping of an unknown object

Kim, Gab-Soon Korean Society for Precision Engineering 2004 International Journal of Precision Engineering and Vol.5 No.3

This paper describes the development of a 6-axis robot's finger force/moment sensor, which measures forces $F_x$(x-direction force), $F_y$and $F_z$, and moments $M_x$ (x-direction moment), $M_y$ and $M_z$ simultaneously, for stable grasping of an unknown object. In order to safely grasp an unknown object using the robot's gripper, the force in the gripping direction and the force in the gravity direction should be measured, and the force control should be performed using the measured forces. Also, the moments $M_x$, $M_y$ and $M_z$ to accurately perceive the position of the object in the grippers should be detected. Thus, the robot's gripper should be composed of 6-axis robot's finger force/moment sensor that can measure forces $F_x$, $F_y$ and $F_z$, and moments $M_x$ $M_y$ and $M_z$ simultaneously. In this paper, the 6-axis robot's finger force/moment sensor for measuring forces $F_x$, $F_y$ and $F_z$, and moments $M_x$ $M_y$ and $M_z$ simultaneously was newly modeled using several parallel-plate beams, designed, and fabricated. The characteristic test of the fabricated sensor was performed, and the result shows that interference errors of the developed sensor are less than 3%. Also, Robot's gripper with the 6-axis robot's finger force/moment sensor for the characteristic test of force control was manufactured, and the characteristic test for grasping an unknown object using the sensors was performed using it. The fabricated gripper could grasp an unknown object stably. Thus, the developed 6-axis robot's finger force/moment sensor can be used for robot's gripper.

지능형 로봇 발을 위한 6축 힘/모멘트센서 개발

김갑순(Gab-Soon Kim),신희준(Hyi-Jun Shin),허덕찬(Duk-Chan Hu),윤정원(Jungwon Yoon) 대한기계학회 2007 대한기계학회 춘추학술대회 Vol.2007 No.5

This paper describes the development of 6-axis force/moment sensor for an intelligent robot’s foot. In order to walk on uneven terrain safely, the foot should perceive the applied forces Fx, Fy, Fz and moments Mx, My, Mz to itself. The applied forces and moments should be measured from a 6-axis force/moment sensor attached to a humanoid robot’s foot(ankle). They in the published paper already have some disadvantage in the size of the sensor, the rated output and so on. The rated output of each component sensor (6-axis force/moment sensor) is very important to design the 6-axis force/moment sensor for precision measurement. Therefore, each sensor should be designed to be gotten similar the rated output under each rated load. So, the sensing elements of the 6-axis force/moment sensor should get lots of design variables. Also, the size of 6-axis force/moment sensor is very important for mounting to robot’s foot. In this paper, a 6-axis force/moment sensor for perceiving forces and moments in a humanoid robot’s foot was developed using many PPBs (parallel plate-beams). The structure of the sensor was newly modeled, and the sensing elements (platebeams) of the sensor were designed using FEM (Finite Element Method) analysis. Then, the 6-axis force/moment sensor was fabricated by attaching strain-gages on the sensing elements, and the characteristic test of the developed sensor was carried out. The rated outputs from FEM analysis agree well with that from the characteristic test.

6축 로봇의 공구중심점 교정 및 틸팅-로터리 테이블의 기하학적 오차 측정

이광일,김도훈,이훈희,양승한 한국정밀공학회 2022 한국정밀공학회지 Vol.39 No.4

Tool-center-point (TCP) calibration and geometric error identification procedures are proposed to improve the accuracy of a 6-axis manipulator with a tilting rotary table. The accuracy of a 6-axis manipulator is affected by the accuracy of TCP calibration. In general, TCP calibration of the 6-axis manipulator uses a conical fixture provided by the manufacturer. However, since a TCP cannot be accurately positioned to the tip of the conical fixture repeatedly, a large positionaldeviation occurs at the calibration depending on the worker proficiency. Thus, accuracies of TCP calibration and the 6-axis manipulator are reduced. In this paper, a 3-DOF measuring device, consisting of a nest with three dial gauges and a precision ball, is developed to calibrate the TCP and to improve the accuracy of the 6-axis manipulator. Then, geometric errors of a tilting rotary table are identified via double ball-bar measurements according to the ISO 10791-6 with TCP initial alignment using an extension fixture. Finally, proposed TCP calibration and geometric error identification procedures are validated experimentally, and they show improvements in positional accuracy by 55 and 90%, respectively.