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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 6, Issue 4 - Nov 2011
Volume 6, Issue 3 - Aug 2011
Volume 6, Issue 2 - May 2011
Volume 6, Issue 1 - Feb 2011
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A Study on ZMP Improvement of Biped Walking Robot Using Neural Network and Tilting
Kim, Byoung-Soo ; Nam, Kyu-Min ; Lee, Soon-Geul ;
The Journal of Korea Robotics Society, volume 6, issue 4, 2011, Pages 301~307
DOI : 10.7746/jkros.2011.6.4.301
Based on the stability criteria of ZMP (Zero Moment Point), this paper proposes an adjusting algorithm that modifies walking trajectory of a bipedal robot for stable walking by analyzing ZMP trajectory of it. In order to maintain walking balance of the bipedal robot, ZMP should be located within a supporting polygon that is determined by the foot supporting area with stability margin. Initially tilting imposed to the trajectory of the upper body is proposed to transfer ZMP of the given walking trajectory into the stable region for the minimum stability. A neural network method is also proposed for the stable walking trajectory of the biped robot. It uses backpropagation learning with angles and angular velocities of all joints with tilting to get the improved walking trajectory. By applying the optimized walking trajectory that is obtained with the neural network model, the ZMP trajectory of the bipedal robot is certainly located within a stable area of the supporting polygon. Experimental results show that the optimally learned trajectory with neural network gives more stability even though the tilting of the pelvic joint has a great role for walking stability.
Motion Planning of Manipulators Using Kinematic Redundancy and ZMP Constraint Condition
Choi, Jae-Yeon ; Yoon, Hyun-Soo ; Yi, Byung-Ju ;
The Journal of Korea Robotics Society, volume 6, issue 4, 2011, Pages 308~316
DOI : 10.7746/jkros.2011.6.4.308
This work deals with development of effective redundancy resolution algorithms for the motion control of manipulator. Differently from the typical kinematically redundant robots that are attached to the fixed ground, the ZMP condition should be taken into account in the manipulator motion in order to guarantee the system stability. In this paper, a new motion planning algorithm for redundant manipulator not fixed to the ground is introduced. A sequential redundancy resolution algorithm is proposed, which ensures the ZMP (Zero Moment Point) stability, the planned operational motion, and additional sub-criteria such as joint limit index. A geometric constraint equation derived by reshaping the existing ZMP equation enables one to employ the sequential redundancy algorithm. The feasibility of the proposed algorithm is verified by simulating a redundant manipulator model.
Design of an Augmented State Feedback Controller for a Wheeled Inverted Pendulum Returning to the Origin
Lee, Se-Han ;
The Journal of Korea Robotics Society, volume 6, issue 4, 2011, Pages 317~322
DOI : 10.7746/jkros.2011.6.4.317
An augmented state feedback controller for a Wheeled Inverted Pendulum (WIP) is proposed in this research. The augmented state feedback controller is able to keep the WIP returning to the origin. Generally, the WIP has both stable and unstable equilibrium points. To keep the WIP over the unstable equilibrium point, the WIP consistently is being controlled. A simple state feedback controller is letting the WIP out of the origin when the center of gravity of the WIP locates out of the schematic center line. In some case of applications, it may not be desirable that the WIP is drifting out of the initial location. The proposed augmented state feedback controller is able to keep the WIP at the initial location whether its center of gravity lies out of the center line or not. Numerical simulations are carried out to show the validation of the augmented sated feedback controller.
KisBot II : New Spherical Robot with Curved Two-pendulum Driving Mechanism
Yoon, Joong-Cheol ; Ahn, Sung-Su ; Lee, Yun-Jung ;
The Journal of Korea Robotics Society, volume 6, issue 4, 2011, Pages 323~333
DOI : 10.7746/jkros.2011.6.4.323
Due to the limited pendulum motion range, the conventional one-pendulum driven spherical robot has limited driving capability. Especially it can not drive parallel direction with center horizontal axis to which pendulum is attached from stationary state. To overcome the limited driving capability of one-pendulum driven spherical robot, we introduce a spherical robot, called KisBot II, with a new type of curved two-pendulum driving mechanism. A cross-shape frame of the robot is located horizontally in the center of the robot. The main axis of the frame is connected to the outer shell, and each curved pendulum is connected to the end of the other axis of the frame respectively. The main axis and pendulums can rotate 360 degrees inside the sphere orthogonally without interfering with each other, also the two pendulums can rotate identically or independent of each other. Due to this driving mechanism, KisBot II has various motion generation abilities, including a fast steering, turning capability in place and during travelling, and four directions including forward, backward, left, and right from stationary status. Experiments for several motions verify the driving efficiency of the proposed spherical robot.
Indoor Mobile Robot Heading Detection Using MEMS Gyro North Finding Approach
Wei, Yuan-Long ; Lee, Min-Cheol ; Kim, Chi-Yen ;
The Journal of Korea Robotics Society, volume 6, issue 4, 2011, Pages 334~343
DOI : 10.7746/jkros.2011.6.4.334
This paper presents a new approach for mobile robot heading detection using MEMS Gyro north finding method in the indoor environment. Based on this, the robot heading angle measurement scheme is proposed; improved north finding theory and algorithm are also explained. Several approaches are applied to confirm system`s precision and effectiveness. In order to find out the heading angle, a single axis MEMS gyroscope to sense the angle between the robot heading direction and the north is used. To reach enough estimation accuracy and reduce detection time, the least square method (LSM) for the signal fitting and parameter estimation is applied. Through a turn-table, we setup a carouseling system to decrease the substantial bias effect on gyroscope`s heading angle. For the evaluation of the proposed method, this system is implemented to the Pioneer robot platform. The performance and heading error are analyzed after the test. From the simulation and experimental results, system`s accuracy, usefulness and adaptability are shown.
Pose Selection of a Mobile Manipulator for a Pick and Place Task
Cho, Kyoung-Rae ;
The Journal of Korea Robotics Society, volume 6, issue 4, 2011, Pages 344~352
DOI : 10.7746/jkros.2011.6.4.344
A mobile manipulator is a system with a robotic manipulator mounted on top of a mobile base. It has both indoor and outdoor applications for transporting or transferring materials. When a user gives commands, they are usually at high levels such as "move the object to the table," or "tidy the room." By intelligently decomposing these complex commands into several subtasks, the mobile manipulator can perform the tasks with a greater efficiency. One of the crucial subtasks for these commands is the pick-and-place task. For the mobile manipulator, selection of a good base position and orientation is essential to accomplishing this task. This paper presents an algorithm that determines one of the position and orientation of a mobile manipulator in order to complete the pick-and-place task without human intervention. Its effectiveness are shown for a mobile manipulator with 9 degrees-of-freedom in simulation.
A Layered Architecture for Robot Automated Services on Ubiquitous Computing Environments
Choi, Jong-Sun ; Choi, Jae-Young ; Cho, Yong-Yun ;
The Journal of Korea Robotics Society, volume 6, issue 4, 2011, Pages 353~364
DOI : 10.7746/jkros.2011.6.4.353
In ubiquitous computing environments, users want to receive the robot services regardless of various physical status or devices such as time, place, various sensors, and high-performance servers. Thus, the ubiquitous service robots have to provide users with automated services according to situational information that they properly recognize. Beyond these problems, robot software has to establish a foundation to support the functions with the network infrastructure that are not able to be solved by a single independent resource. On the basis of a robot middleware that is capable of minimizing dependencies among hierarchy structures, the robot software also has to provide execution environment to control the flow of robot application services. In this paper, we propose a layered architecture to provide users with automated services through ubiquitous robots. The proposed architecture is based on CAWL (Context-Aware Workflow Language) and RSEL (Robot Services Execution Language). CAWL easily represents the flow of robot services from user application service levels, and RSEL is able to support the composition and reusability of robot services through abstraction of robot device services. In our experiments, we applied the proposed architecture to an example of "booth guide robot service".
A Survey on Teacher`s Cognition for the Improvement of Robotics Education in Public Education
Kim, Sung-Ae ; Ji, Soon-Duk ;
The Journal of Korea Robotics Society, volume 6, issue 4, 2011, Pages 365~372
DOI : 10.7746/jkros.2011.6.4.365
The purpose of this study is to improve robotics education in public education. This study was conducted with 157 secondary school teachers regardless of their gender, age and majors. The results are as follows: First, 68.2% of the respondents (81.2% of the STEM(Science, Technology, Engineering, Mathematics)-related teachers) thought that robotics education should be included in public education because it will be a very important area in the future. Second, 73.3% of respondents (89.3% of the STEM-related teachers) agreed that robotics education will be worth teaching as a regular subject. The most important reason was that they thought the robots would be an excellent tool to initiate their class participation and increase their study motivation. Third, the results from this survey showed that the technology teachers would be the best suitable instructors for robotics education. Lastly, teachers felt a great deal of burden to teach robotics although they thought robotics education was necessary. In order to implement robotics education in public school, teachers think it is necessary to take professional training. In addition, teachers should be supported with the reduction in their workload along with sufficient fundings, educational robots such as LEGO MINDSTORMS, and newly designed teaching materials.