Browsing by Author "Wang, Jyun-Ji"

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A spatial-color mean-shift object tracking algorithm with scale and orientation estimation
(2008-12-01)
Hu, Jwu-Sheng
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Juan, Chung-Wei
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Wang, Jyun-Ji
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電控工程研究所
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Institute of Electrical and Control Engineering
In this paper, an enhanced mean-shift tracking algorithm using joint spatial-color feature and a novel similarity measure function is proposed. The target image is modeled with the kernel density estimation and new similarity measure functions are developed using the expectation of the estimated kernel density. With these new similarity measure functions, two similarity-based mean-shift tracking algorithms are derived. To enhance the robustness, the weighted-background information is added into the proposed tracking algorithm. Further, to cope with the object deformation problem, the principal components of the variance matrix are computed to update the orientation of the tracking object, and corresponding eigenvalues are used to monitor the scale of the object. The experimental results show that the new similarity-based tracking algorithms can be implemented in real-time and are able to track the moving object with an automatic update of the orientation and scale changes. (C) 2008 Elsevier B.V. All rights reserved.
Behavior control of the mobile robot for accompanying in front of a human
(2012)
Ho, Daniel M.
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Hu, Jwu-Sheng
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Wang, Jyun-Ji
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電機工程學系
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Department of Electrical and Computer Engineering
Different behaviors for the companion robot have already been extensively studied in the field of human-robot interaction. However, the accompanying "in front of the leader" behavior presented on this paper is a useful and challenging behavior that has been overlooked by existing works. In this paper we explain the motivation behind this study and propose control strategy to implement this behavior.
Design of Sensing System and Anticipative Behavior for Human Following of Mobile Robots
(2014-04-01)
Hu, Jwu-Sheng
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Wang, Jyun-Ji
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Ho, Daniel Minare
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電機工程學系
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Department of Electrical and Computer Engineering
The human-following behavior design for mobile robots is considered in this paper. In particular, the issue should be addressed from the perspective of human-robot interaction since humans are aware of the following actions. This makes the problem quite different from human tracking where recognition and location accuracy are the main concerns. An anticipative human-following behavior is proposed by incorporating the human model. The human model is constructed using relevant scientific studies about human walk and social interaction, allowing the robot to predict the human trajectory and to take preemptive action. To realize the idea, it is necessary to have a robust sensing system that is capable of tracking the human location persistently. In this paper, we also propose a sensing system based on a novel 3-D mean-shift algorithm on RGBD camera. The system performance is assessed through experimental evaluation of three specific human-following scenarios: following from behind, following on the side, and following in front. Each of these scenarios has its particularities and applications, thus providing insight about the effectiveness and usability of anticipative behavior.
GLOVE PUPPET MANIPULATING SYSTEM
(2010-04-15)
HU, Jwu-Sheng
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Wang, Jyun-Ji
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Sun, Guan-Qun
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Tang, Chi-Him
A glove puppet manipulating system comprises a control module for generating control signals base on movements of human hand and a robot electrically connecting the control module installed inside a glove puppet. The robot has a body manipulating apparatus disposed on a foundation to manipulate the body of the glove puppet to rotate, a pair of hand manipulating apparatuses disposed on the body manipulating apparatus to manipulate the hands of the glove puppet to swivel, and a head manipulating apparatus interposed between the hand manipulating apparatuses on the body manipulating apparatus to manipulate the head of the glove puppet to nod.
Kinematic Calibration of Manipulator Using Single Laser Pointer
(2012-01-01)
Hu, Jwu-Sheng
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Wang, Jyun-Ji
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Chang, Yung-Jung
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電子工程學系及電子研究所
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交大工研院聯合研發中心
This paper proposes a robot kinematic calibration system including a laser pointer installed on the manipulator, a stationary camera, and a planar surface. The laser pointer beams to the surface, and the camera observes the projected laser spot. The position of the laser spot is computed according to the geometrical relationships of line-plane intersection. The laser spot position is sensitive to slight difference of the end-effector pose due to the extensibility of laser beam. Inaccurate kinematic parameters cause inaccurate calculation of the end-effector pose, and then the laser spot position by the forward estimation is deviated from the one by camera observation. For calibrating the robot kinematics, the optimal solution of kinematic parameters is obtained by minimizing the laser spot position difference between the forward estimation and camera measurement via the nonlinear optimization method. The proposed kinematic calibration system is cost-efficient and flexible for any manipulator. The proposed method is validated by simulation and experiment.
Self-balancing Control and Manipulation of a Glove Puppet Robot on a Two-wheel Mobile Platform
(2009)
Hu, Jwu-Sheng
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Wang, Jyun-Ji
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Sun, Guan-Cyun
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電控工程研究所
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Institute of Electrical and Control Engineering
This video shows a continuing work of the glove puppet robot presented before [1]. The major improvement from the previous work is to mount the 9-DOF mechanism, which mimicking a glove puppet manipulation, on a two-wheel mobile platform. The platform provides agile movements of the robot but itself is an unstable system. Hence, a self-balancing controller is implemented by considering the motion as well as configuration variation of the upper body (the 9-DOF mechanism). The control law utilizes the principle of computed torque method with online identification of related parameters using various sensors including an accelerometer. The incline angle is obtained by fusing a gyroscope and a tilt sensor. Under the balancing control, the forward motion of the robot is achieved by giving a desired tilt angle profile. To minimize the footprint of electronics, the controller is implemented using an 8-bit single-chip microcontroller. Further, to enhance the interaction capability of the system, a simple gesture coding using dynamic time warping[2] identification method with Markov model is implemented for the data glove to recognize the puppet gesture by human hand.
Surface Coordinate Measurement Using Un-calibrated Cameras and Laser Pointer Equipped Robot Manipulator
(2011)
Hu, Jwu-Sheng
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Wang, Jyun-Ji
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電機工程學系
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Department of Electrical and Computer Engineering
This paper presents a new method to measure three-dimensional coordinate data, corresponding to any pixel of a camera. The system configuration includes multiple un-calibrated cameras, a laser pointer, and a manipulator. The manipulator can control the orientation and position of the laser pointer, and the laser beam spot on the surface can be observed by each camera. Based on the visual servo algorithm, the proposed method generates different laser lines which the observation of these laser spots matches the desired pixel indices for each camera. The intersection of multiple lines is the measurement of the surface point. The simulation results demonstrate the accuracy of the measurement and test the influence of several parameters. The real experiment for measuring the position of corners in a chessboard is implemented.
The Glove Puppet Robot: X-puppet
(2008)
Hu, Jwu-Sheng
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Wang, Jyun-Ji
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Sun, Guan-Qun
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電控工程研究所
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Institute of Electrical and Control Engineering
The glove puppet is a traditional art in Taiwan. The master puppeteer manipulates the glove puppets and brings each animated puppet character to life. In this work, we attempt to robotize the glove puppet (called X-puppet) along with three types of manipulation interface including a motion editor, a data glove and a motion capture system. The motion editor is a higher level puppet motion composer that creates and combines sequences of control in a timely fashion. The special designed data glove uses a minimum number of sensors to achieve puppet manipulation. It measures the gesture data and maps to the motion of X-puppet in real-time. The motion capture system can extract the puppet's motion from the video and then control the X-puppet to simulate the action. The whole system represents an effort to give this traditional art a new style of performance.
The proof of a better performance by one-stage than two-stage estimation in robot calibration
(2015)
Hu, Jwu-Sheng
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Wang, Jyun-Ji
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電機工程學系
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Department of Electrical and Computer Engineering
Calibration of a robot manipulator requires an external instrument to measure its end-effector locations. If the parameters are estimated directly from the measurements, it is called one-stage estimation. Otherwise, it is called two-stage estimation. It was previously observed that two-stage estimation has the drawback of error propagation. Theoretically, it is known that for linear system, the minimum variance is achieved using the best linear unbiased estimator in one-stage estimation. However, the two-stage estimation can also achieve the minimum variance under certain conditions. In this paper, the statistical properties of both are explored in detail under a newly established mathematical fact. The result can be extended to the nonlinear estimation problem via approximation. Simulations of robot calibration by a coordinate measuring machine and eye-in-hand camera are conducted and the results confirm the theoretical analysis.