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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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The Journal of Korea Robotics Society
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Journal DOI :
The Korea Robotics Society
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Volume & Issues
Volume 10, Issue 4 - Nov 2015
Volume 10, Issue 3 - Aug 2015
Volume 10, Issue 2 - May 2015
Volume 10, Issue 1 - Feb 2015
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Force and Pose control for Anthropomorphic Robotic Hand with Redundancy
Yee, Gun Kyu ; Kim, Yong Bum ; Kim, Anna ; Kang, Gitae ; Choi, Hyouk Ryeol ;
The Journal of Korea Robotics Society, volume 10, issue 4, 2015, Pages 179~185
DOI : 10.7746/jkros.2015.10.4.179
The versatility of a human hand is what the researchers eager to mimic. As one of the attempt, the redundant degree of freedom in the human hand is considered. However, in the force domain the redundant joint causes a control issue. To solve this problem, the force control method for a redundant robotic hand which is similar to the human is proposed. First, the redundancy of the human hand is analyzed. Then, to resolve the redundancy in force domain, the artificial minimum energy point is specified and the restoring force is used to control the configuration of the finger other than the force in a null space. Finally, the method is verified experimentally with a commercial robot hand, called Allegro Hand with a force/torque sensor.
Slip Ratio Reduction and Moving Balance Control of a Ball-bot using Mecanum Wheel
Park, Young Sik ; Kim, Su Jeong ; Byun, Soo Kyung ; Lee, Jang Myung ;
The Journal of Korea Robotics Society, volume 10, issue 4, 2015, Pages 186~192
DOI : 10.7746/jkros.2015.10.4.186
This paper proposes a robust balance and driving control for omni-directional ball robot(generally called ball-bot) with two axis mecanum wheel. Slip between ball and mecanum wheel actuator inevitably occurs along diagonal axis due to its instantaneous strong torque. In order to reduce and saturate slip, exact distance calculation scheme especially for rotational movement is essential. So this research solved Euler-Lagrange dynamics for proposed two axis ball robot based on practical mechanical modeling. Robust balance control was carried out by PID controller according to the pitch and roll angles of ball robot by using sensor fusion between AHRS and wheel encoder. Proposed PID controller enhances stability by reducing steady state error and settling time. Proposed slip control algorithm for omni-directional ball robot has been demonstrated by experiments for balance control and arbitrary driving control.
Slip Considered Design and Analysis Pincers-type Gripper for Seizing Heavy-weighted Cylindrical Objects
Choi, Jung Hyun ; An, Jinung ; Lee, Sang Mun ; Jang, Myeong Eon ;
The Journal of Korea Robotics Society, volume 10, issue 4, 2015, Pages 193~199
DOI : 10.7746/jkros.2015.10.4.193
This paper dealt with a pincers-type gripper being able to grip a heavy-weighted cylindrical object having various size with itself. This gripper should be designed to seize the objects without any change of jaw shape. Grasping achieved equilibrium after the object slipped on the jaw while grasping it. To cope with this situation, we suggested the slip considered gripper design procedure based on grasping equilibrium. The obtained slip condition can provide a limit friction coefficient depending on the contact angle when initiating contact between jaw and object. Consequently, the gripping force and the required actuating force can be calculated. In order to verify the proposed slip condition, the simulations were performed using a dynamic software.
Modelling of variable coefficient of restitution and its application to impact analysis of dynamic systems
Ryu, Hwan-Taek ; Choi, Jae-Yeon ; Kwon, Young-Hun ; Yi, Byung-Ju ;
The Journal of Korea Robotics Society, volume 10, issue 4, 2015, Pages 200~212
DOI : 10.7746/jkros.2015.10.4.200
In classical dynamics, the coefficient of restitution is one of variables to estimate the amount of impulse. In general, we have considered the coefficient of restitution as a constant value. However, coefficient of restitution (COR) is the function of contact material and colliding velocity. Furthermore, COR is also a function of contact area. Thus, without considering the variable characteristic of COR, the actual motion of an object just after impact is not the same as we expect. A general COR model is proposed in this work and its effectiveness is verified through a cart impact experiment and its result is applied to simulation of a ball impact problem. A three-degree-of-freedom manipulator is employed as a test-bed.
A Wireless-Communicated Spirally Column-Climbing Robot with a Manipulator
Lee, Suk-Woo ; Ha, Sung-Min ; Kang, Chul-Goo ;
The Journal of Korea Robotics Society, volume 10, issue 4, 2015, Pages 213~222
DOI : 10.7746/jkros.2015.10.4.213
This paper presents a column-climbing robot with a mechanical manipulator, which can spirally go up and down a column using wheels. The developed robot can do useful works using the manipulator at the top of a column, e.g., electric pole while communicating wirelessly with an operator panel. It is driven using a battery without any power cables, and the average duration of power is at least one hour. The robot has a function to detect a work object using an optical sensor installed at the bottom of the manipulator. The spirally column-climbing robot developed is demonstrated by experimental works and also by showing it at an exhibition.
Hand Raising Pose Detection in the Images of a Single Camera for Mobile Robot
Kwon, Gi-Il ;
The Journal of Korea Robotics Society, volume 10, issue 4, 2015, Pages 223~229
DOI : 10.7746/jkros.2015.10.4.223
This paper proposes a novel method for detection of hand raising poses from images acquired from a single camera attached to a mobile robot that navigates unknown dynamic environments. Due to unconstrained illumination, a high level of variance in human appearances and unpredictable backgrounds, detecting hand raising gestures from an image acquired from a camera attached to a mobile robot is very challenging. The proposed method first detects faces to determine the region of interest (ROI), and in this ROI, we detect hands by using a HOG-based hand detector. By using the color distribution of the face region, we evaluate each candidate in the detected hand region. To deal with cases of failure in face detection, we also use a HOG-based hand raising pose detector. Unlike other hand raising pose detector systems, we evaluate our algorithm with images acquired from the camera and images obtained from the Internet that contain unknown backgrounds and unconstrained illumination. The level of variance in hand raising poses in these images is very high. Our experiment results show that the proposed method robustly detects hand raising poses in complex backgrounds and unknown lighting conditions.
Solution Space of Inverse Differential Kinematics
Kang, Chul-Goo ;
The Journal of Korea Robotics Society, volume 10, issue 4, 2015, Pages 230~244
DOI : 10.7746/jkros.2015.10.4.230
Continuous-path motion control such as resolved motion rate control requires online solving of the inverse differential kinematics for a robot. However, the solution space of the inverse differential kinematics related to Jacobian J is not well-established. In this paper, the solution space of inverse differential kinematics is analyzed through categorization of mapping conditions between joint velocities and end-effector velocity of a robot. If end-effector velocity is within the column space of J, the solution or the minimum norm solution is obtained. If it is not within the column space of J, an approximate solution by least-squares is obtained. Moreover, this paper introduces an improved mapping diagram showing orthogonality and mapping clearly between subspaces, and concrete examples numerically showing the concept of several subspaces. Finally, a solver and graphics user interface (GUI) for inverse differential kinematics are developed using MATLAB, and the solution of inverse differential kinematics using the GUI is demonstrated for a vertically articulated robot.