• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1992.04a
• /
• pp.127-132
• /
• 1992

To relize the future intelligent robot the development of a special-purpose processor for a coordinate transformation is evidently challenging task. In this case the complexity of a hardware architecture strongly depends on the adopted algorithm. In this paper we have used an inverse kinemetics algorithm based on incremental unit computation method. This method considers the 3-axis articulated robot as the combination of two types of a 2-axis robot: polar robot and 2-axis planar articulated one. For each robot incremental units in the joint and Cartesian spaces are defined. With this approach the calculation of the inverse Jacobian matrix can be realized through a simple combinational logic gate. Futhermore, the incremental computation of the DDA integrator can be used to solve the direct kinematics. We have also designed a hardware architecture to implement the proposed algorithm. The architecture consists of serveral simple unitsl. The operative unit comprises several basic operators and simple data path with a small bit-length. The hardware architecture is realized byusing the EPLD. For the straight-line motion of the KAIST arm we have obtained maximum end effector's speed of 12.6 m/sec by adopting system clock of 8 MHz.

• Journal of the Korean Society for Precision Engineering
• /
• v.25 no.4
• /
• pp.148-153
• /
• 2008

Although manual traction, one of pain therapies, was applied in clinic to relief pain, the study was rare on the manual force and displacement of ligaments at knee joint during manual traction. The aim of this study is to quantify not only manual force at knee joint but also elongated displacement of joint ligament by C-arm scanning and motion analysis. Twenty-one healthy subjects were tested with manual traction from grade I to grade III under neutral position by a physical therapist. We calculated traction force using joint farces of both hands and elongated displacement of joint ligament were measured. The results showed that traction forces by C-arm scanning analysis were averagely 1.67-fold greater than those by motion analysis, but elongated displacements were instead averagely 2.36-fold smaller than motion analysis. Finally, we could estimate relationship between traction force and elongated displacement at knee joint by two methods.

• Journal of the Korean Society for Precision Engineering
• /
• v.18 no.10
• /
• pp.116-126
• /
• 2001

This paper suggests a numerical method to find optimal geometric path and minimum-time motion for a spatial 6-link manipulator arm (PUMA 560 type). To find a minimum-time motion, the optimal geometric paths minimizing 2 different dynamic performance indices are searched first, and the minimum-time motions are searched on these optimal paths. In the algorithm to find optimal geometric paths, the objective functions (performance indices) are selected to minimize joint velocities, actuator forces or the combinations of them as well as to avoid one static obstacle. In the minimum-time algorithm the traveling time is expressed by the power series including 21 terms. The coefficients of the series are obtained using nonlinear programming to minimize the total traveling time subject to the constraints of velocity-dependent actuator forces.

• Journal of the Korean Society for Precision Engineering
• /
• v.19 no.1
• /
• pp.127-134
• /
• 2002

This study present a direct steering system using rack and pinion for ultra-small vehicles. The traditional small vehicles for special use had the limitation of space by reason of short wheel tread. These vehicles has adopted a indirect steering system or a center arm system for steering. The disadvantages of these system were deterioration of gear efficiency and increase of parts. For direct-linkage to both knuckles, steering system is made up of out-side tie rods, tie-rod ends, and gear box. Thus, the proposed system has a minimum number of parts. The experimental results show a maximum efficiency at minimum steering angle and a minimum clearance circle. These effects were accomplished by adopting a Ackerman-Jantaud theory.

• Journal of the Korean Society for Precision Engineering
• /
• v.15 no.8
• /
• pp.156-164
• /
• 1998

IMS is a more advanced manufacturing system than FMS. However, IMS do not have sufficient performance for the work in the various and uncertain environment, because of the difficulty of the work and occurrence of the unexpected condition. If IMS is hard to work properly, teleoperation system can support it by using the human's consideration and judgment. The master mechanism is a basic component of the teleoperation system and the development of the useful one is important for efficiency of the work. A master mechanism of exoskeleton type can increase the work efficiency, mobility and harmony between a working robot and an operator. This paper describes an arm-harness of exoskeleton type, which is able to drive a robot according to judgment. This device is applied to a robot system for evaluating the system performance through the experiment.

• Journal of the Korean Society for Precision Engineering
• /
• v.26 no.9
• /
• pp.31-37
• /
• 2009

• Journal of the Korean Society for Precision Engineering
• /
• v.26 no.9
• /
• pp.45-52
• /
• 2009

• The Journal of Korea Robotics Society
• /
• v.11 no.4
• /
• pp.293-299
• /
• 2016

In this article art performing applications of industrial dual-arm robots are introduced. It was real collaboration among robot researchers and artist. Artist designed the performance to use dual-arm robot. Robot researchers collaborated with artist by providing robotic constraints and configuring robot motion. Two art performances were configured with two industrial dual-arm robots. In both performance robots carry objects to be used as moving screens. Both performances rely on the high power and high precision of robots. In addition human-like appearance make those performances be familiar to public.

• Journal of the Korean Society for Precision Engineering
• /
• v.28 no.9
• /
• pp.1048-1053
• /
• 2011

Recently, robots have been used in surgical area. Robotic surgery in Minimally Invasive Surgery gives many advantages to surgeons and patients both. This study introduce a robotic assistant to improve the safety of telerobotic Minimally Invasive Surgical procedures. The master-slave system is applied to the telerobotic surgical system with the master arm, which control the system, and slave robot which operates the surgery on the patient body. By using a 3-DOF master arm, the surgeon can control the 6-DOF surgical robot under the constraint of fulcrum point. This paper explains the telerobotic surgical system and confirms the system with the precision of the robot control related to the fulcrum point to enhance the safety.

• International Journal of Precision Engineering and Manufacturing
• /
• v.8 no.3
• /
• pp.20-23
• /
• 2007

To calibrate precision autocollimators, the Korean Research Institute of Standards and Science (KRISS) has built a small angle generator using a laser interferometer. The system is based on a sine bar mechanism in which the angle is determined from the ratio of two lengths. The rotational angle is measured by the angle interferometer and the heterodyne laser interferometer detects the relative displacement of two retro-reflectors attached to the rotating arm. The distance between the two retro-reflectors of the laser angle interferometer is self-calibrated by an index table positioned on the rotating arm. The resolution of the system is 0.002 seconds, and the accuracy is better than 0.04 seconds within a measuring range of $\pm$1 degree. The small angle generator can also be used with an index table that can divide one circle into 1440 angles. The combined system can generate any angle over 360 degrees to an accuracy of 0.11 seconds.