• The Journal of Korea Robotics Society
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• v.19 no.2
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• pp.169-175
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• 2024

In this study, we developed control system for stable teleoperation of supermicrosurgical robot platform. The supermicrosurgical robot platform is designed to perform precise anastomosis with micro vessels ranging from 0.3 mm to 0.7 mm. The robotic assistance could help more precise manipulation then manual surgery with the help of motion scaling and tremor filtering. However, since the robotic system could cause several vulnerabilities, control system for stable teleoperation should be preceded. Therefore, we first designed control system including inverse kinematics solver, clutch error interpolator and finite state machine. The inverse kinematics solver was designed to minimized inertial motion of the manipulator and tested by applying orientational motion. To make robot slowly converges to the leader's orientation when orientational error was occurred during clutch, the SLERP was used to interpolate the error. Since synchronized behavior of two manipulators and independent behavior of manipulator both exist, two layered finite state machines were designed. Finally, the control system was evaluated by experiment and showed intended behavior, while maintaining low pose error.

• Journal of Institute of Control, Robotics and Systems
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• v.18 no.12
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• pp.1106-1114
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• 2012

To achieve synchronized motion between a wearable robot and a human user, the redundancy must be resolved in the same manner by both systems. According to the seven DOF (Degrees of Freedom) human arm model composed of the shoulder, elbow, and wrist joints, positioning and orientating the wrist in space is a task requiring only six DOFs. Due to this redundancy, a given task can be completed by multiple arm configurations, and thus there exists no unique mathematical solution to the inverse kinematics. This paper presents analysis on the kinematic and dynamic aspect of the human arm movement and their effect on the redundancy resolution of the human arm based on a seven DOF manipulator model. The redundancy of the arm is expressed mathematically by defining the swivel angle. The final form of swivel angle can be represented as a linear combination of two different swivel angles achieved by optimizing different cost functions based on kinematic and dynamic criteria. The kinematic criterion is to maximize the projection of the longest principal axis of the manipulability ellipsoid for the human arm on the vector connecting the wrist and the virtual target on the head region. The dynamic criterion is to minimize the mechanical work done in the joint space for each two consecutive points along the task space trajectory. As a first step, the redundancy based on the kinematic criterion will be thoroughly studied based on the motion capture data analysis. Experimental results indicate that by using the proposed redundancy resolution criterion in the kinematic level, error between the predicted and the actual swivel angle acquired from the motor control system is less than five degrees.

• Journal of Korea Game Society
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• v.3 no.2
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• pp.24-29
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• 2003

The market of digital avatar with internet and digital technology is increasing rapidly. The users want to express any free-formed motion of their avatars in the cyber space. The user s motion capturing method as the avatar's motion can express any free-formed motion of the avatar in real-time but the methods are expensive and inconvenient. In this paper, we proposed a new method of expressing any free-formed motion of the avatar in real-time. The proposed method is an algorithm for real-time control of a 3D avatar in symmetry-formed free motion. Specially, the algorithm aims at the motion control of a 3D avatar for online dancing games. The proposed algorithm uses the skeleton character model and controls any one of two hands of the character model by a joystick with two sticks. In the symmetry-formed motion, the position and orientation of one hand can determine the position and orientation of the other hand. And the position and orientation of a hand as an end-effector can determine the pose of the arm by Inverse Kinematics. So the algorithm can control the symmetry-formed free motions of two arms by one joystick with two sticks. In the dance game, the algorithm controls the arm motion by the joystick and the other motion by the motion captured DB.

• Reproductive and Developmental Biology
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• v.35 no.1
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• pp.47-54
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• 2011

Endocrine disruptors bind to hormone receptors on sperm membrane, therefore spermatozoa are potentially a useful model for examining estrogenic activities of endocrine disruptors. The objective of this study was to compare the effects of two xenoestrogenic compounds [genistein (Gen) and 4-tert-octylphenol (OP)] to those of two steroids [estrogen ($E_2$) and progesterone ($P_4$)] on boar sperm % motility and motion kinematics of in vitro. Porcine spermatozoa were incubated with various concentrations ($0.001{\sim}100\;{\mu}M$) of each chemical for 15 or 30 min, and then assessed % motility and sperm motion kinematics using computer assisted sperm analyzer (CASA). Each chemical decreased sperm % motility, and OP decreased VSL and VAP compared with untreated control(p<0.05). $E_2$ stimulated the motion kinematic changes except VCL. Moreover, Gen had effects on VCL and VAP alterations after 30 min incubation. In summary, since all chemicals studied effectively altered sperm % motility and motion kinematics, it was concluded that porcine spermatozoa could be a useful model for in vitro screening of potential endocrine disruptors.

• Journal of Institute of Control, Robotics and Systems
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• v.6 no.12
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• pp.1093-1098
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• 2000

This paper presents an efficient algorithm for including the kinematic calibration data into the motion controller to improve the positioning accuracy of the manipulators. Rather than spending several iterations for finding the inverse solution of the calibrated kinematics, our approach requires only the nominal inverse solution and the calibrated forward kinematics for providing a better position command promptly. Thus, real-time application is guaranteed whenever the manipulators nominal inverse solution can be expressed in a closed form. Experimental results show that the line tracking performances can be remarkably improved by employing our algorithm.

• Transactions on Control, Automation and Systems Engineering
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• v.1 no.1
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• pp.8-15
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• 1999

One of the main reason advocating redundant manipulators' superiority in application is that they can afford to optimize a dexterity measure, for example the manipulability measure. However, to obtain the gradient of the manipulability is not an easy task in case of general manipulator with high degrees of redundancy. This article proposes a method to compute the gradient of the manipulability, based on recursive algorithm to compute the Jacobian and its derivative using Denavit-Hartenberg parameters only. To characterize the null motion of redundant manipulators, the null space matrix using square minors of the Jacobian is also proposed. With these capabilities, the inverse kinematics of a redundant manipulator system can be done automatically. The result is easily extended to dual manipulator system using the relative kinematics.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1731-1734
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• 2003

We propose a unmaned integrating control system based-on Windows XP version Off-Line Programming System which can simulate a Robot model in 3D Graphics space in this paper. The robot with 4 and 6 axes modeled SM5 and AM1 respectively were adopted as an objective model. Forward kinematics, inverse kinematics and robot dynamics modeling were included in the developed off-line program. The interface between users and the off-line programming system in the Windows XP's graphic user interface environment was also studied. The developing language is Microsoft Visual C++. Graphic libraries, OpenGL, by silicon Graphics, Inc. were utilized for 3D Graphics.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.04a
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• pp.319-326
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• 2003

We propose a unmaned integrating control system based-on Windows XP version Off-Line Programming System which can simulate a Robot model in 3D Graphics space in this paper. The industrial robot with 4 and 6 axes modeled SM5 and AMI respectively were adopted as an objective model. Forward kinematics, inverse kinematics and robot dynamics modeling were included in the developed off-line program. The interface between users and the off-line programming system in the Windows XP's graphic user interface environment was also studied. The developing language is Microsoft Visual C++. Graphic libraries, OpenGL, by silicon Graphics, Inc. were utilized for 3D Graphics.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.3
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• pp.250-256
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• 2015

We present a novel method to model the body posture of a worm for vision-based automatic monitoring and analysis. The worm considered in this study is a Caenorhabditis elegans (C. elegans), which is popularly used for research in biological science and engineering. We model the posture by an open chain of a few curved or rigid line segments, in contrast to previously published approaches wherein a large number of small rigid elements are connected for the modeling. Each link segment is represented by only two parameters: an arc angle and an arc length for a curved segment, or an orientation angle and a link length for a straight line segment. Links in the proposed method can be readily related using the Denavit-Hartenberg convention due to similarities to the kinematics of an articulated manipulator. Our method was tested with real worm images, and accurate results were obtained.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1823-1824
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• 2008

We propose a remote controlled robot manipulator using force feedback joystick. User can control easily 5 d.o.f robot manipulator in 3 demensional space using general joystick. A force sensor attached in developed gripper sends signal to main robot controller so as to know gripper grasp the object. The signal also sent to user through force feedback joystick. We designed a dexterous 5 d.o.f robot manipulator analysis the kinematics and inverse kinematics. The robot was simply developed using serial RC motor. As a main robot controller, we use 32bit MPU(AT91SAM7256) and micro C/OS. To show the validity of our developed robot, a several experiments were demonstrated.