Loc Vo - Academia.edu (original) (raw)
Papers by Loc Vo
ICCAS 2010, 2010
International Conference on Control, Automation and Systems 2010 Oct. 27-30, 2010 in KINTEX, Gyeo... more International Conference on Control, Automation and Systems 2010 Oct. 27-30, 2010 in KINTEX, Gyeonggi-do, Korea ... A Study on Traversability of Quadruped Robot in Rough Terrain ... Vo-Gia Loc1, Ig Mo Koo1, Tran Duc Trong1, Ho Moon Kim1, Hyungpil Moon1, ...
Mobility and freedom are two driving forces for research in wireless sensor networks. Recent adva... more Mobility and freedom are two driving forces for research in wireless sensor networks. Recent advances in hardware development, offering low-cost, low-power sensor devices open up for an exciting research field where only the imagination can stop us from developing exiting and revolutionary applications. In the medical field sensor networks can be used to remotely monitor physiological parameters such as heartbeat or blood pressure or patients, and report to the hospital when some parameters are altered. This is a huge research field, and much research will be done in the coming years to cope with recently unsolved issues. This Master's thesis will present and describe a customized, tailor-made, and optimized cross-layer implementation of a communication protocol for medical purposes. The research platform is based on the IEEE802.15.4/ZigBee protocol that is widely popular for sensor networks applications. ZigBee based wireless sensor network finds interesting applications in med...
Proceedings of the 2005 IEEE International Conference on Robotics and Automation
One of the traditional problems of the walking robot moving in 3D environment is how to negotiate... more One of the traditional problems of the walking robot moving in 3D environment is how to negotiate the boundary of two plain surfaces, which may be convex or concave. In this paper the planning method in the transition region of the boundary is proposed in terms of geometrical view. In each case such as concave and convex, the trajectory that robot moves along has to be determined and the foot positions of the robot associated with the trajectory has to be estimated. The trajectory of the body is derived from the geometrical analysis of the relationship between the robot and the environment. And the position of each foot is estimated by using parameter associated with the hip and the ankle of the robot. The validity of the proposed method is demonstrated through simulations and experiments are performed in the concave and convex environments with limited slope angle.
2007 IEEE/RSJ International Conference on Intelligent Robots and Systems, 2007
Abstract In this paper, a new biomimetic control method for a quadruped walking robot is propose... more Abstract In this paper, a new biomimetic control method for a quadruped walking robot is proposed. The method is derived by the observation of the gravity load receptor and stimulus-reaction mechanism of quadrupeds' locomotion, and the study of the stances on ...
2009 IEEE/RSJ International Conference on Intelligent Robots and Systems, 2009
Aiming to real easy application in several quadruped robot platforms, this paper introduces a new... more Aiming to real easy application in several quadruped robot platforms, this paper introduces a new method of modeling central pattern generators (CPG) to control quadruped locomotion. Not only can this new model generate all the primary gaits of quadrupeds stably with limit cycle effect, but it also has the ability of tuning the periodic outputs with arbitrary waveforms. The core idea is to combine strong points of two mathematical tools: Fourier series and Recurrent neural networks. In addition, a new biomimetic controller is also introduced using the proposed CPG model and several reflex modules. Finally, dynamic simulations are performed to validate the efficiency of the proposed controller.
2009 IEEE/RSJ International Conference on Intelligent Robots and Systems, 2009
Improvement of the adaptability of a quadruped robot in rough terrain is studied in this paper. F... more Improvement of the adaptability of a quadruped robot in rough terrain is studied in this paper. First, the position and posture of the body of the robot are adjusted to maximize the number of choices for foot placement of the next swing leg. The more choices the robot has to select the next suitable foothold, the better it will be to cope with rough terrain. Second, an effective foothold search algorithm is developed. The foothold search algorithm not only tries to find a valid foothold but also tries to maintain high adaptability of the robot. For implementing the algorithm, some new concepts such as potential swing direction, complementary kinematic margin and elliptical set of candidate footholds are also proposed. The effectiveness of this procedure in improving the adaptability of a quadruped robot moving in challenging terrain is verified in both simulation and experiment.
International Journal of Control, Automation and Systems, 2009
Abstract: In this paper, we present a control method for a quadruped walking robot inspired from ... more Abstract: In this paper, we present a control method for a quadruped walking robot inspired from the locomotion of quadrupeds. A simple and useful framework for controlling a quadruped walking robot is presented, which is obtained by observing the stimulus-reaction mechanism, the ...
2013 European Modelling Symposium, 2013
In this paper, we present a study on dynamic simulation to assist designing a high performance co... more In this paper, we present a study on dynamic simulation to assist designing a high performance compliant humanoid robot. An open source dynamic simulator is introduced which includes the rigid body and actuator dynamics of the full humanoid robot. A set of representative tasks for humanoid robot in rescue operations are chosen and simulated. The data from these tasks are used in sizing the motor and transmission gear for each joint of the robot. It is shown that in the representative tasks, the most critical joint of the robot (in terms of power consumption) is the knee joint. Furthermore, a recently proposed optimization method is used to obtain the value of passive compliance for each joint. The data obtained from simulation studies are used for designing the new humanoid robot.
Robotics and Autonomous Systems, 2011
This paper presents a study on improving the traversability of a quadruped walking robot in 3D ro... more This paper presents a study on improving the traversability of a quadruped walking robot in 3D rough terrains. The key idea is to exploit body movement of the robot. The position and orientation of the robot are systematically adjusted and the possibility of finding a valid foothold for the next swing is maximized, which makes the robot have more chances
Robotics and Autonomous Systems, 2010
In this paper, a general study on improving adaptability of quadruped walking and climbing robot ... more In this paper, a general study on improving adaptability of quadruped walking and climbing robot in complex environment is presented. First, a sensing system composed of range and gyroscope sensors in a novel arrangement is developed. By combining the sensing signals and the internal state of the robot, the surface geometry of the environment is sufficiently reconstructed in real-time. Secondly, a planning algorithm for the robot to overcome the reconstructed environment is conducted. Based on the reshaped surface, the planning algorithm not only provides the exact body trajectory and foot positions but also the adaptability of the robot in a specific environment. A method to improve the adaptability of the walking and climbing robot is also introduced. Thanks to the adherent ability of the robot, the center of gravity of the robot is allowed to move outside the support polygon to increase the reach-ability of the next swing leg. Finally, the effectiveness of the proposed approach is verified by the performances of the experiments in complex environments using a quadruped walking and climbing robot named MRWALLSPECT IV.
![Research paper thumbnail of Structure-Function Analysis of Human alpha1[IMAGE]3Fucosyltransferases](https://attachments.academia-assets.com/93684824/thumbnails/1.jpg)
](Journal of Biological Chemistry, 1995
Biology of Reproduction, 2000
Vitelline envelopes are composed of glycoproteins that participate in sperm-egg interactions duri... more Vitelline envelopes are composed of glycoproteins that participate in sperm-egg interactions during the initial stages of fertilization. In Xenopus laevis, the vitelline envelope is composed of at least 4 glycoproteins (ZPA, ZPB, ZPC, and ZPX). A sperm binding assay involving the covalent coupling of envelope glycoproteins to silanized glass slides was developed. In our assay, sperm bound to the egg envelopes derived from oviposited eggs but not activated eggs. The majority of the egg envelope ligand activity for sperm binding was derived from the complex Nlinked oligosaccharides of ZPC. This sperm binding involved Nacetylglucosamine and fucose residues, as binding was abolished after treatment with cortical granule -N-acetylglucosaminidase and commercial -N-acetylglucosaminidases and was reduced by 44% after treatment with ␣-fucosidase. Although both the envelope glycoproteins ZPA and ZPC possessed independent ligand activity, ZPC was the major ligand for sperm binding (75%). Mixing of isolated ZPA, ZPB, and ZPC in a ratio of 1:4:4 (equal to that in the egg envelope) resulted in sperm binding that was greater than that of the sum of the separate components. The egg glycoproteins acted in synergy to increase sperm binding. Thus, ZPC possessed both independent and hetero-oligomeric-dependent ligand activities for sperm binding.
Biology of Reproduction, 2003
The Xenopus laevis egg vitelline envelope is composed of five glycoproteins (ZPA, ZPB, ZPC, ZPD, ... more The Xenopus laevis egg vitelline envelope is composed of five glycoproteins (ZPA, ZPB, ZPC, ZPD, and ZPX). As shown previously, ZPC is the primary ligand for sperm binding to the egg envelope, and this binding involves the oligosaccharide moieties of the glycoprotein (Biol. Reprod., 62:766-774, 2000). To understand the molecular mechanism of sperm-egg envelope binding, we characterized the N-linked glycans of the vitelline envelope (VE) glycoproteins. The N-linked glycans of the VE were composed predominantly of a heterogeneous mixture of highmannose (5-9) and neutral, complex oligosaccharides primarily derived from ZPC (the dominant glycoprotein). However, the ZPA N-linked glycans were composed of acidic-complex and high-mannose oligosaccharides, ZPX had only high-mannose oligosaccharides, and ZPB lacked N-linked oligosaccharides. The consensus sequence for N-linked glycosylation at the evolutionarily conserved residue N 113 of the ZPC protein sequence was glycosylated solely with high-mannose oligosaccharides. This conserved glycosylation site may be of importance to the threedimensional structure of the ZPC glycoproteins. One of the complex oligosaccharides of ZPC possessed terminal -N-acetyl-glucosamine residues. The same ZPC oligosaccharide species isolated from the activated egg envelopes lacked terminal -Nacetyl-glucosamine residues. We previously showed that the cortical granules contain -N-acetyl-glucosaminidase (J. Exp. Zool., 235:335-340, 1985). We propose that an alteration in the oligosaccharide structure of ZPC by glucosaminidase released from the cortical granule reaction is responsible for the loss of sperm binding ligand activity at fertilization.
ICCAS 2010, 2010
International Conference on Control, Automation and Systems 2010 Oct. 27-30, 2010 in KINTEX, Gyeo... more International Conference on Control, Automation and Systems 2010 Oct. 27-30, 2010 in KINTEX, Gyeonggi-do, Korea ... A Study on Traversability of Quadruped Robot in Rough Terrain ... Vo-Gia Loc1, Ig Mo Koo1, Tran Duc Trong1, Ho Moon Kim1, Hyungpil Moon1, ...
Mobility and freedom are two driving forces for research in wireless sensor networks. Recent adva... more Mobility and freedom are two driving forces for research in wireless sensor networks. Recent advances in hardware development, offering low-cost, low-power sensor devices open up for an exciting research field where only the imagination can stop us from developing exiting and revolutionary applications. In the medical field sensor networks can be used to remotely monitor physiological parameters such as heartbeat or blood pressure or patients, and report to the hospital when some parameters are altered. This is a huge research field, and much research will be done in the coming years to cope with recently unsolved issues. This Master's thesis will present and describe a customized, tailor-made, and optimized cross-layer implementation of a communication protocol for medical purposes. The research platform is based on the IEEE802.15.4/ZigBee protocol that is widely popular for sensor networks applications. ZigBee based wireless sensor network finds interesting applications in med...
Proceedings of the 2005 IEEE International Conference on Robotics and Automation
One of the traditional problems of the walking robot moving in 3D environment is how to negotiate... more One of the traditional problems of the walking robot moving in 3D environment is how to negotiate the boundary of two plain surfaces, which may be convex or concave. In this paper the planning method in the transition region of the boundary is proposed in terms of geometrical view. In each case such as concave and convex, the trajectory that robot moves along has to be determined and the foot positions of the robot associated with the trajectory has to be estimated. The trajectory of the body is derived from the geometrical analysis of the relationship between the robot and the environment. And the position of each foot is estimated by using parameter associated with the hip and the ankle of the robot. The validity of the proposed method is demonstrated through simulations and experiments are performed in the concave and convex environments with limited slope angle.
2007 IEEE/RSJ International Conference on Intelligent Robots and Systems, 2007
Abstract In this paper, a new biomimetic control method for a quadruped walking robot is propose... more Abstract In this paper, a new biomimetic control method for a quadruped walking robot is proposed. The method is derived by the observation of the gravity load receptor and stimulus-reaction mechanism of quadrupeds' locomotion, and the study of the stances on ...
2009 IEEE/RSJ International Conference on Intelligent Robots and Systems, 2009
Aiming to real easy application in several quadruped robot platforms, this paper introduces a new... more Aiming to real easy application in several quadruped robot platforms, this paper introduces a new method of modeling central pattern generators (CPG) to control quadruped locomotion. Not only can this new model generate all the primary gaits of quadrupeds stably with limit cycle effect, but it also has the ability of tuning the periodic outputs with arbitrary waveforms. The core idea is to combine strong points of two mathematical tools: Fourier series and Recurrent neural networks. In addition, a new biomimetic controller is also introduced using the proposed CPG model and several reflex modules. Finally, dynamic simulations are performed to validate the efficiency of the proposed controller.
2009 IEEE/RSJ International Conference on Intelligent Robots and Systems, 2009
Improvement of the adaptability of a quadruped robot in rough terrain is studied in this paper. F... more Improvement of the adaptability of a quadruped robot in rough terrain is studied in this paper. First, the position and posture of the body of the robot are adjusted to maximize the number of choices for foot placement of the next swing leg. The more choices the robot has to select the next suitable foothold, the better it will be to cope with rough terrain. Second, an effective foothold search algorithm is developed. The foothold search algorithm not only tries to find a valid foothold but also tries to maintain high adaptability of the robot. For implementing the algorithm, some new concepts such as potential swing direction, complementary kinematic margin and elliptical set of candidate footholds are also proposed. The effectiveness of this procedure in improving the adaptability of a quadruped robot moving in challenging terrain is verified in both simulation and experiment.
International Journal of Control, Automation and Systems, 2009
Abstract: In this paper, we present a control method for a quadruped walking robot inspired from ... more Abstract: In this paper, we present a control method for a quadruped walking robot inspired from the locomotion of quadrupeds. A simple and useful framework for controlling a quadruped walking robot is presented, which is obtained by observing the stimulus-reaction mechanism, the ...
2013 European Modelling Symposium, 2013
In this paper, we present a study on dynamic simulation to assist designing a high performance co... more In this paper, we present a study on dynamic simulation to assist designing a high performance compliant humanoid robot. An open source dynamic simulator is introduced which includes the rigid body and actuator dynamics of the full humanoid robot. A set of representative tasks for humanoid robot in rescue operations are chosen and simulated. The data from these tasks are used in sizing the motor and transmission gear for each joint of the robot. It is shown that in the representative tasks, the most critical joint of the robot (in terms of power consumption) is the knee joint. Furthermore, a recently proposed optimization method is used to obtain the value of passive compliance for each joint. The data obtained from simulation studies are used for designing the new humanoid robot.
Robotics and Autonomous Systems, 2011
This paper presents a study on improving the traversability of a quadruped walking robot in 3D ro... more This paper presents a study on improving the traversability of a quadruped walking robot in 3D rough terrains. The key idea is to exploit body movement of the robot. The position and orientation of the robot are systematically adjusted and the possibility of finding a valid foothold for the next swing is maximized, which makes the robot have more chances
Robotics and Autonomous Systems, 2010
In this paper, a general study on improving adaptability of quadruped walking and climbing robot ... more In this paper, a general study on improving adaptability of quadruped walking and climbing robot in complex environment is presented. First, a sensing system composed of range and gyroscope sensors in a novel arrangement is developed. By combining the sensing signals and the internal state of the robot, the surface geometry of the environment is sufficiently reconstructed in real-time. Secondly, a planning algorithm for the robot to overcome the reconstructed environment is conducted. Based on the reshaped surface, the planning algorithm not only provides the exact body trajectory and foot positions but also the adaptability of the robot in a specific environment. A method to improve the adaptability of the walking and climbing robot is also introduced. Thanks to the adherent ability of the robot, the center of gravity of the robot is allowed to move outside the support polygon to increase the reach-ability of the next swing leg. Finally, the effectiveness of the proposed approach is verified by the performances of the experiments in complex environments using a quadruped walking and climbing robot named MRWALLSPECT IV.
Journal of Biological Chemistry, 1995
Biology of Reproduction, 2000
Vitelline envelopes are composed of glycoproteins that participate in sperm-egg interactions duri... more Vitelline envelopes are composed of glycoproteins that participate in sperm-egg interactions during the initial stages of fertilization. In Xenopus laevis, the vitelline envelope is composed of at least 4 glycoproteins (ZPA, ZPB, ZPC, and ZPX). A sperm binding assay involving the covalent coupling of envelope glycoproteins to silanized glass slides was developed. In our assay, sperm bound to the egg envelopes derived from oviposited eggs but not activated eggs. The majority of the egg envelope ligand activity for sperm binding was derived from the complex Nlinked oligosaccharides of ZPC. This sperm binding involved Nacetylglucosamine and fucose residues, as binding was abolished after treatment with cortical granule -N-acetylglucosaminidase and commercial -N-acetylglucosaminidases and was reduced by 44% after treatment with ␣-fucosidase. Although both the envelope glycoproteins ZPA and ZPC possessed independent ligand activity, ZPC was the major ligand for sperm binding (75%). Mixing of isolated ZPA, ZPB, and ZPC in a ratio of 1:4:4 (equal to that in the egg envelope) resulted in sperm binding that was greater than that of the sum of the separate components. The egg glycoproteins acted in synergy to increase sperm binding. Thus, ZPC possessed both independent and hetero-oligomeric-dependent ligand activities for sperm binding.
Biology of Reproduction, 2003
The Xenopus laevis egg vitelline envelope is composed of five glycoproteins (ZPA, ZPB, ZPC, ZPD, ... more The Xenopus laevis egg vitelline envelope is composed of five glycoproteins (ZPA, ZPB, ZPC, ZPD, and ZPX). As shown previously, ZPC is the primary ligand for sperm binding to the egg envelope, and this binding involves the oligosaccharide moieties of the glycoprotein (Biol. Reprod., 62:766-774, 2000). To understand the molecular mechanism of sperm-egg envelope binding, we characterized the N-linked glycans of the vitelline envelope (VE) glycoproteins. The N-linked glycans of the VE were composed predominantly of a heterogeneous mixture of highmannose (5-9) and neutral, complex oligosaccharides primarily derived from ZPC (the dominant glycoprotein). However, the ZPA N-linked glycans were composed of acidic-complex and high-mannose oligosaccharides, ZPX had only high-mannose oligosaccharides, and ZPB lacked N-linked oligosaccharides. The consensus sequence for N-linked glycosylation at the evolutionarily conserved residue N 113 of the ZPC protein sequence was glycosylated solely with high-mannose oligosaccharides. This conserved glycosylation site may be of importance to the threedimensional structure of the ZPC glycoproteins. One of the complex oligosaccharides of ZPC possessed terminal -N-acetyl-glucosamine residues. The same ZPC oligosaccharide species isolated from the activated egg envelopes lacked terminal -Nacetyl-glucosamine residues. We previously showed that the cortical granules contain -N-acetyl-glucosaminidase (J. Exp. Zool., 235:335-340, 1985). We propose that an alteration in the oligosaccharide structure of ZPC by glucosaminidase released from the cortical granule reaction is responsible for the loss of sperm binding ligand activity at fertilization.