Transactions of the Korean Society of Mechanical Engineers A, 2004
In this paper, we deal with a precise position synchronous control of four-axes system which is w... more In this paper, we deal with a precise position synchronous control of four-axes system which is working under various load disturbances. Each axis driving system is consisted of a speed controller and an acceleration controller as an inner loop instead of conventional current control scheme. The acceleration control plays an important roll to suppress load disturbances quickly. Also, each axis is coupled by a maximum position synchronous error comparison to minimize position synchronous errors according to integration of speed differency. As a result, the proposed system enables precise synchronous control with good robustness against load disturbances during transient as well as steady state. The stability and robustness of the proposed system are investigated through its frequency characteristic and numerical simulations. Finally, experimental results under load disturbances demonstrate the effectiveness of the proposed control system fur four-axes position synchronous control.
In this paper, a robust motion tracking control algorithm for robotic manipulators is proposed wh... more In this paper, a robust motion tracking control algorithm for robotic manipulators is proposed where the higher-order system uncertainties are taken into account. The control structure consists of two main parts: a model-based precompensation part and a robust nonlinear controller one. Specifically, with knowledge of possible upper bounds on uncertainties, we propose the nonadaptive version of robust controller. Stability and
... Sam-Sang, You* and Seok-Kwon, Jeong** (Received February l, 1996) ... An (nxn) identity matri... more ... Sam-Sang, You* and Seok-Kwon, Jeong** (Received February l, 1996) ... An (nxn) identity matrix 0n : A n-dimensional null vector 0n : A (n null matrices dirn(o) : The dimension of (o) rs (A) : The range space of matrix A rk (A) : The rank of matrix A * Assistant Professor, School of ...
Transactions of the Institute of Measurement and Control, 2004
This paper deals with the modelling and robust control synthesis of intelligent vehicles for gene... more This paper deals with the modelling and robust control synthesis of intelligent vehicles for general lateral motion in intelligent transportation system applications. The lateral vehicle dynamics for general lane following are firstly derived in a unified framework. Based on a coprime factor plant description, the two-degree-of freedom based H1 loop-shaping control scheme is presented for lane keeping and changing manoeuvres simultaneously. The resulting robust controller is generally of high order and has to be reduced for real implementation. Also, the reduced-order controller is evaluated in both the frequency- and the time-domain analysis. Finally, it is found that the proposed automatic steering controller provides robust performance and stability for a given vehicle manoeuvring in the presence of parameter variations of vehicles.
Journal of the Korean Society of Marine Engineering, 2008
Umbilical cord blood has been recently considered an attractive potential alternative as a source... more Umbilical cord blood has been recently considered an attractive potential alternative as a source of stem cell transplantation to curing diseases such as leukemia, cancers, immune disorders. Normally the stored system of the umbilical cord blood specimen is equipped with a computer-controlled robotic arm that enables the samples to locate the identification places in liquid nitrogen tank at regulated temperature as about . As the half of robotic arm is in the air and the rest part is submerged in liquid nitrogen, the temperature of robotic arm varies from ambient to liquid nitrogen temperature. In this study the temperature variation of upper part of arm above tank lid was thermally analysed by using the commercial code of Ansys. The result of analysis was that the upper part of robotic arm was seriously frozen due to heat transfer from liquid nitrogen as low as -. In order to solve the frost problem of robotic arm, small PTFE tube block as resistance material was introduced into the lower part of tank lid instead of the whole stainless steel(SUS) robotic arm. The results showed that the temperature of robotic arm above the lid was higher enough, and this method would be one of the very effective measure to solve the problem.
2006 SICE-ICASE International Joint Conference, 2006
We are developing a new type of human-sized BWR (biped walking robot) driven by the closed-chain ... more We are developing a new type of human-sized BWR (biped walking robot) driven by the closed-chain type of joint actuator. Each leg of the robot is composed of 6 joints, arms have 12 joints, and head has 4 joints. In all, a 29 degree-of-freedom BWR is under developing. The weight of the robot is 75 (Kg) with 166cm tall, but was designed to be capable of supporting 120Kg. The BWR was designed to walk autonomously such that all leg joints are actuated by 150W DC motors/drivers and DC batteries and controllers which are boarded. An analysis on the four-bar-link mechanism applied to the joint actuator and on the structure of the BWR capable of supporting heavy load is shown. The design specification of the actuating motor for the BWR is analyzed through the torque analysis and experiment on the four-bar-link actuator. A walking performance is shown with heavy load
Proceedings of IEEE International Conference on Systems, Man and Cybernetics
Abstract This paper presents a dynamic compensation methodology for the robust trajectory trackin... more Abstract This paper presents a dynamic compensation methodology for the robust trajectory tracking control of uncertain robot manipulators. To improve the tracking performance of the system, a full model-based feedforward compensation with continuous VS-type robust ...
SUMMARYThis paper presents analysis and experimental verifications of a new robot manipulator wit... more SUMMARYThis paper presents analysis and experimental verifications of a new robot manipulator with five degrees of freedom developed for the buffing operation of shoes. First, the forward and inverse kinematics are analyzed. Next, an analytic closed-form solution is rigorously derived for the joint angles corresponding to the position and orientation of the end-effector in Cartesian coordinates. A control system, including input/output interfaces and the related electronic system, is designed for the control of the mechanical structure of the buffing robot. Then, peripheral systems integrated with the conveyer, transfer device, and fixture device are designed for the sequential buffing process of shoes. Also, a graphic user interface (GUI) program including the forward/inverse kinematics, control algorithm, and communication program to interact the robot with the peripheral systems is developed by using visual C++ language. A new flexible toolholder (FTH) is proposed to compensate f...
Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science, 2013
This paper deals with an experimental investigation to measure the frictional pressure drops for ... more This paper deals with an experimental investigation to measure the frictional pressure drops for two-phase flow boiling in a micro-channel with a hydraulic diameter of 500 µm. First, the experimental study is performed under the test conditions: heat fluxes ranging from 100 to 400 kW/m2, vapor qualities from 0 to 0.2, and mass fluxes of 200, 400 and 600 kg/m2s. Then, the frictional pressure drop during flow boiling is estimated using two models: the homogeneous model and the separated flow model. The experimental results show that the two-phase multiplier decreases with the increase of mass flux. In addition, the measured pressure drops are compared with those from a few correlation models available for macro-scales and mini/micro-scales. Finally, the present paper proposes a new correlation for two-phase frictional pressure drops in mini/micro-scales. This correlation model is developed based on the Chisholm constant C as a function of two-phase Reynolds and Weber numbers. It is fo...
Transactions of the Korean Society of Mechanical Engineers A, 2004
In this paper, we deal with a precise position synchronous control of four-axes system which is w... more In this paper, we deal with a precise position synchronous control of four-axes system which is working under various load disturbances. Each axis driving system is consisted of a speed controller and an acceleration controller as an inner loop instead of conventional current control scheme. The acceleration control plays an important roll to suppress load disturbances quickly. Also, each axis is coupled by a maximum position synchronous error comparison to minimize position synchronous errors according to integration of speed differency. As a result, the proposed system enables precise synchronous control with good robustness against load disturbances during transient as well as steady state. The stability and robustness of the proposed system are investigated through its frequency characteristic and numerical simulations. Finally, experimental results under load disturbances demonstrate the effectiveness of the proposed control system fur four-axes position synchronous control.
In this paper, a robust motion tracking control algorithm for robotic manipulators is proposed wh... more In this paper, a robust motion tracking control algorithm for robotic manipulators is proposed where the higher-order system uncertainties are taken into account. The control structure consists of two main parts: a model-based precompensation part and a robust nonlinear controller one. Specifically, with knowledge of possible upper bounds on uncertainties, we propose the nonadaptive version of robust controller. Stability and
... Sam-Sang, You* and Seok-Kwon, Jeong** (Received February l, 1996) ... An (nxn) identity matri... more ... Sam-Sang, You* and Seok-Kwon, Jeong** (Received February l, 1996) ... An (nxn) identity matrix 0n : A n-dimensional null vector 0n : A (n null matrices dirn(o) : The dimension of (o) rs (A) : The range space of matrix A rk (A) : The rank of matrix A * Assistant Professor, School of ...
Transactions of the Institute of Measurement and Control, 2004
This paper deals with the modelling and robust control synthesis of intelligent vehicles for gene... more This paper deals with the modelling and robust control synthesis of intelligent vehicles for general lateral motion in intelligent transportation system applications. The lateral vehicle dynamics for general lane following are firstly derived in a unified framework. Based on a coprime factor plant description, the two-degree-of freedom based H1 loop-shaping control scheme is presented for lane keeping and changing manoeuvres simultaneously. The resulting robust controller is generally of high order and has to be reduced for real implementation. Also, the reduced-order controller is evaluated in both the frequency- and the time-domain analysis. Finally, it is found that the proposed automatic steering controller provides robust performance and stability for a given vehicle manoeuvring in the presence of parameter variations of vehicles.
Journal of the Korean Society of Marine Engineering, 2008
Umbilical cord blood has been recently considered an attractive potential alternative as a source... more Umbilical cord blood has been recently considered an attractive potential alternative as a source of stem cell transplantation to curing diseases such as leukemia, cancers, immune disorders. Normally the stored system of the umbilical cord blood specimen is equipped with a computer-controlled robotic arm that enables the samples to locate the identification places in liquid nitrogen tank at regulated temperature as about . As the half of robotic arm is in the air and the rest part is submerged in liquid nitrogen, the temperature of robotic arm varies from ambient to liquid nitrogen temperature. In this study the temperature variation of upper part of arm above tank lid was thermally analysed by using the commercial code of Ansys. The result of analysis was that the upper part of robotic arm was seriously frozen due to heat transfer from liquid nitrogen as low as -. In order to solve the frost problem of robotic arm, small PTFE tube block as resistance material was introduced into the lower part of tank lid instead of the whole stainless steel(SUS) robotic arm. The results showed that the temperature of robotic arm above the lid was higher enough, and this method would be one of the very effective measure to solve the problem.
2006 SICE-ICASE International Joint Conference, 2006
We are developing a new type of human-sized BWR (biped walking robot) driven by the closed-chain ... more We are developing a new type of human-sized BWR (biped walking robot) driven by the closed-chain type of joint actuator. Each leg of the robot is composed of 6 joints, arms have 12 joints, and head has 4 joints. In all, a 29 degree-of-freedom BWR is under developing. The weight of the robot is 75 (Kg) with 166cm tall, but was designed to be capable of supporting 120Kg. The BWR was designed to walk autonomously such that all leg joints are actuated by 150W DC motors/drivers and DC batteries and controllers which are boarded. An analysis on the four-bar-link mechanism applied to the joint actuator and on the structure of the BWR capable of supporting heavy load is shown. The design specification of the actuating motor for the BWR is analyzed through the torque analysis and experiment on the four-bar-link actuator. A walking performance is shown with heavy load
Proceedings of IEEE International Conference on Systems, Man and Cybernetics
Abstract This paper presents a dynamic compensation methodology for the robust trajectory trackin... more Abstract This paper presents a dynamic compensation methodology for the robust trajectory tracking control of uncertain robot manipulators. To improve the tracking performance of the system, a full model-based feedforward compensation with continuous VS-type robust ...
SUMMARYThis paper presents analysis and experimental verifications of a new robot manipulator wit... more SUMMARYThis paper presents analysis and experimental verifications of a new robot manipulator with five degrees of freedom developed for the buffing operation of shoes. First, the forward and inverse kinematics are analyzed. Next, an analytic closed-form solution is rigorously derived for the joint angles corresponding to the position and orientation of the end-effector in Cartesian coordinates. A control system, including input/output interfaces and the related electronic system, is designed for the control of the mechanical structure of the buffing robot. Then, peripheral systems integrated with the conveyer, transfer device, and fixture device are designed for the sequential buffing process of shoes. Also, a graphic user interface (GUI) program including the forward/inverse kinematics, control algorithm, and communication program to interact the robot with the peripheral systems is developed by using visual C++ language. A new flexible toolholder (FTH) is proposed to compensate f...
Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science, 2013
This paper deals with an experimental investigation to measure the frictional pressure drops for ... more This paper deals with an experimental investigation to measure the frictional pressure drops for two-phase flow boiling in a micro-channel with a hydraulic diameter of 500 µm. First, the experimental study is performed under the test conditions: heat fluxes ranging from 100 to 400 kW/m2, vapor qualities from 0 to 0.2, and mass fluxes of 200, 400 and 600 kg/m2s. Then, the frictional pressure drop during flow boiling is estimated using two models: the homogeneous model and the separated flow model. The experimental results show that the two-phase multiplier decreases with the increase of mass flux. In addition, the measured pressure drops are compared with those from a few correlation models available for macro-scales and mini/micro-scales. Finally, the present paper proposes a new correlation for two-phase frictional pressure drops in mini/micro-scales. This correlation model is developed based on the Chisholm constant C as a function of two-phase Reynolds and Weber numbers. It is fo...
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