• Journal of the Korea Safety Management & Science
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• v.25 no.1
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• pp.15-21
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• 2023

In modern society, the delivery service market has grown explosively due to rapid changes in social structure and the recent COVID-19 pandemic. Therefore, various problems such as injury to workers and an increase in human accidents are occurring due to the loading and unloading of parcels. In order to solve this problem, domestic company n is developing a "robot-based cargo loading and unloading system". In developing a new technology system, quantitative reliability targets should be set for efficient operation and development. In this paper, reliability analysis was conducted through field data for the pneumatic gripper of the "robot-based cargo loading system". The reliability of the failure data was analyzed to estimate the distribution parameters and MTTF. Random data was derived for the probability of occurrence of a failure with the estimated value. By repeating the simulation to predict the number and year of failures according to the estimated parameters of the probability distribution, it was proposed as a method that reflects realistic probabilities rather than calculating with simple arithmetic using the average MTTF previously used in the field.

• The Journal of Korea Robotics Society
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• v.19 no.1
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• pp.31-38
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• 2024

A mobile manipulator is capable of handling a wide range of workspaces by overcoming the limitations of mobility inherent in existing fixed-base manipulators. To simulate the mobile manipulator, two contact operations should be considered in the physics engines. One of these operations is the grasp stability between the gripper and the object, while the other involves the contact between the wheels of the mobile robot and the ground during driving. However, it is still difficult to choose an appropriate physics engine for simulating these contact operations of the mobile manipulator. In this paper, the performance of physics engines for simulating the mobile manipulator is evaluated. Firstly, the grasp stability of the physics engine is quantitatively evaluated based on the contact force discontinuity. Secondly, when the mobile robot is controlled by open or closed-loop control methods, differences in the path taken by the mobile robot depending on the physics engine are analyzed. To assess the performance of robot simulation, three dynamic simulators-MuJoCo, CoppeliaSim, and IsaacSim-are used along with five physics engines: MuJoCo, Newton, ODE, Bullet, and PhysX.

• Journal of the Korean Society of Industry Convergence
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• v.18 no.3
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• pp.173-180
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• 2015

In this paper, we propose a new precise control technology of robotic gripper for assembling and handling of part. When a robot manipulator interacts mechanically with its environment to perform tasks such as assembly or edge-finishing, the end-effector is thereby constrained by the environment. Therefore grasping force control is very important, since it increases safety due to monitoring of contact force. A comparison of various force control architecture is reported. Different force control methods can often be configured to achieve similar results for a given task, and the choice of control algorithm depends strongly on the application or on the characteristics of a particular robot. In the research, the adjustable gripping force can be controlled and improved the accuracy using the artificial intelligence techniques.

• Journal of Biosystems Engineering
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• v.23 no.6
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• pp.629-634
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• 1998

Factory-style plant production system aims to produce the standardized horticultural products with high quality and cleanness. In Korea, researches for year-round leaf vegetables production system are in progress and the most of them are focused on environment control. Automating technologies for harvesting, transporting and grading need to be developed. A lettuce harvesting system applicable to the plant factory was studied. It was composed of an articulated robot with a cutter and a gripper, lettuce feeding conveyor and air blower. Success rate of the developed system was 94.7 %. The system carried out harvesting a lettuce smoothly and the harvesting time was about 6 seconds per lettuce. The results showed a feasibility of robotic lettuce harvesting.

• Journal of Biosystems Engineering
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• v.13 no.2
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• pp.9-17
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• 1988

This study was carried out to develop an agricultural robot for fruit harvesting. As the first step an experimental manipulator and its control system were constructed. The articulated manipulator driven by DC motors has 3 degrees-of-freedom. The manipulator has a gripper adequate for fruit harvesting and an upper arm which forms a kind of guiding channel so thai harvested fruit can pass through. Point-to-point control of joints are accomplished by a digital control system with a PID controller which consists of optical shaft encoders, power amplifiers using PWM, a microcomputer and a software. The microcomputer also computes the positions of manipulator and sequence of motions. The motion of the manipulator was to slow and rough that it would need further improvement.

• The Journal of Korea Robotics Society
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• v.16 no.3
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• pp.207-215
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• 2021

There is a risk of serious injury to workers who work at height in pier construction process. By using auto climbing formwork system that does not need to dismantle and reinstall formworks, it is possible to improve work efficiency and safety of workers. However, auto climbing formwork system still requires workers to work on a pier for rebar connection works and so on. In order to eliminate works by workers on the pier, robot manipulators with special end effectors are proposed. Through analysis of works on the pier, three specialized end effectors which are a gripper, a rebar coupler press, and a concrete vibrator, are suggested. Also, new pier construction scenario by the suggested system is confirmed using 3d modeling. It is expected that the proposed system and method enables pier construction without workers on piers. It will increase safety and efficiency of pier construction.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.4
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• pp.563-569
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• 2012

In the semiconductor and display device production processes, the handling of sensitive objects needs new carrying technology. Floating carrying motion is a practical alternative solution for non-contact handling of parts and substrates. This paper presents a study of through paths inside the air pressure pick-up head to generate the floating motion. The air motion by conceptual designed paths inside the head gradually develops positive pressure and vacuum between narrow objects. Positive pressure occurs through the head tip before discharging outside of the head. Negative pressure is developed by evacuating the inside head bottom as result of the radial flow connecting the vertical through-holes. The numerical analysis was done to figure out the stable levitation caused by the two acting forces between surfaces. In comparing with the standard case that the levitation gap gets 0.7-0.9 mm, it confirms the suggested head characteristics to show floating capacity in accordance with the head size, number of through-hole, and locations of through-hole in succession of conceptual design for a prototype.

• Journal of Animal Environmental Science
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• v.6 no.2
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• pp.105-112
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• 2000

The objective of this study was to determine the teat locations and to develop a teat cup handling system operated by a robot. The results of this study were summarized as follows: 1. The teat cup attaching and detaching operation system developed in this study consists of a control computer, a five-dimensional robot(PERFORMER-MK2), a DC servo gripper, a robot controller, two CCD-cameras (WV-vp410), an image grabber board(DT3153), a model cow, and a teat cup unit. 2. The coordinates of teat locations were measured by a stereo image processing unit. The error ranges of teats coordinates measured were (x, y, z) = (0.83, 1.95, 0.81) mm. When those were transferred into the Robot Coordinate System(RCS) coordinate, the total error ranges measured were x = 0.9 mm, y = 2.0 mm, z = 0.9 mm. 3. The rates of success of teat cup attaching and detaching operation by a robot system were 91.5% on average; the operation time needed were 27.8 sec. Total working hours for the teat cup handling including image processing were 86.1 sec.

• Korean Journal of Construction Engineering and Management
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• v.19 no.6
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• pp.115-123
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• 2018

The primary objective of this study is to develop an all-in-one based steel pipe pile cutting robot prototype that improves the conventional steel pipe pile head cutting work in safety, quality, and productivity. For this, the following research works are conducted sequentially; 1)literature review and expert survey, 2)selection of core technology using AHP analysis, 3)deduction of detail design, 4)verification of structural stability, 5)development of full-scale prototype. As a result leveling laser and laser detector(94.46), plasma cutter(96.72), rotary grapple(98.45) are selected as a core technologies. As an outcome, it is analyzed that gripper, cylinder pivot bracket and gripper base are structurally stable. Their maximum stresses are shown as 43.0%, 19.4%, 5.3% compared to their yield strength respectively. The development of full-scale prototype in this study will be utilized for the development of the all-in-one attachment based steel pipe pile cutting robot commercialization model.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.649-652
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• 2005

The camera cellular phone has a large portion of cellular phone market in recent year. The variety of a customer demand makes a fast model change and the spatial resolution is changed from VGA to multi-mega pixel. The 1.3 mega pixel (MP) camera cellular phone was first released into the Korean market in October 2003. The major cellular phone companies released a 2MP camera cellular phone that supports zoom function and a 2MP camera cellular phone is settled down with the Korea cellular phone market. It makes a keen competition in price and demands automation for phone camera module. There is an increasing requirement for the automatic assembly to correspond to a fast model change. The hard automation techniques that rely on dedicated manufacturing system are too inflexible to meet this requirement. Therefore in this study, this system is designed with the flexibility concept in order to cope with phone camera module change. The system has a same platform that has X-Y-Z motion or X-Z motion with ${\mu}m$order accuracy. It has a special gripper according to the type of a component to be put together. If the camera model changes, the gripper may be updated to fit for the camera module. The controller of this system acquires the data sets that have the information about the assembly part by the tray. This information is obtained ahead of an inspection step. The controller excludes an inferior part to be assembled by using this information to diminish the inferior goods. The assembly jig used in this system has a function of self adjustment that reduces the tact time and also diminish the inferior goods. Finally, the intelligent assembly system for phone camera module will be designed to get a flexibility to meet model change and a high productivity with a high reliability.