• International Journal of Precision Engineering and Manufacturing
• /
• v.2 no.3
• /
• pp.34-40
• /
• 2001

Robot manipulator has highly nonlinear dynamics. Therefore the control of multi-link robot arms is a challenging and difficult problem. In this paper a decentralized adaptive fuzzy sliding mode scheme is developed for control of robot manipulators. The proposed scheme does not require an accurate manipulator dynamic model, yet it guarantees asymptotic trajectory tracking despite gross robot parameter variations. Numerical simulation for decentralized control of a 3-axis PUMA arm will also be included.

• Journal of Power Electronics
• /
• v.14 no.6
• /
• pp.1147-1156
• /
• 2014

This study proposes a quasi-fixed-frequency hysteresis current tracking control strategy for modular multilevel converters (MMCs) on the basis of voltage partition principle. First, by monitoring the grid voltage and the deviation between the output and reference currents, the output voltage is determined, thus prompting the output current to quickly and efficiently track the given current. Second, the voltages of the upper/lower capacitor of the arm and the voltages between the upper and lower arms are balanced by combining these arms with virtual loop mapping and arm voltage balance control, respectively. In particular, the proposed method is designed for any level and number of sub-modules. The validity of the proposed method is verified by simulations and experimental results of a five-level MMC prototype.

• Journal of Pharmacopuncture
• /
• v.18 no.2
• /
• pp.33-41
• /
• 2015

Objectives: The present study evaluated the effects of sa-am acupuncture (SAA) simpo-jeongkyeok (SPJK) treatment on the blood pressure (BP), pulse rate (PR), and body temperature (BT) of patients with hwa byung (HB). Methods: This patient assessor blind, randomized, placebo controlled trial included 50 volunteers, divided randomly into two groups. The treatment group underwent SPJK (PC9, LR1, PC3, KI10) while the control (sham) group received minimal needle insertion at non acupoints. The BP in both arms, PR, and BT at several acupoints were measured before and after treatment at the $1^{st}$, $2^{nd}$, $3^{rd}$, and $4^{th}$ visits and before treatment at the follow-up visit. We analyzed data by using the repeated measured analysis of variance (RM ANOVA), Mann-Whitney U, and wilcoxon signed rank tests; differences at P < 0.05 were considered significant. Results: No significant differences in the systolic blood pressure (SBP), diastolic blood pressure (DBP) and PR between the treatment and control group were observed at each visit. However, the decrease in the SBP for the treatment group before and after each visit was significantly higher than it was in the control group. The SBP in both arms in the treatment group was decreased between visits 1 and 2, 1 and 3, 1 and 4, and 1 and follow-up. The DBP in both arms and in the right arm between visits 1 and 3 in the treatment group showed decreases. A minimal BT increase for treatment at CV06 and CV12 and a minimal BT decrease for treatment at CV17 and (Ex) Yintang were found. Patients in the treatment group who visited more frequently experienced a greater decrease in the PR, but that effect was not maintained. Conclusion: The results suggest that SAA SPJK treatment has instant positive effects on the BP, PR, and BT in patients with HB, but the effects on the BP and PR are not maintained.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2000.11a
• /
• pp.721-724
• /
• 2000

This paper has been demonstrated to be essential to successful telemanipulator control when the communication delay between master arms in the operator control station and telemanipulators in the remote site. This paper includes the human dynamics to generate a control command, the monitoring force feedback in order to robust under short time delays and the controller not to requre the derivative of interaction forces. Simulation results suggest that, the proposed control system should be superior to conventional systems in terms of performance and robustness under short time delays.

• 제어로봇시스템학회:학술대회논문집
• /
• 2005.06a
• /
• pp.2126-2131
• /
• 2005

Interactions of a humanoid with a human are important, when the humanoid is requested to provide people with human-friendly services in unknown or uncertain environment. Such interactions may require more complicated and human-like behaviors from the humanoid. In this work the arm motions of a human are discussed as the early stage of human motion imitation by a humanoid. A motion capture system is used to obtain human-friendly arm motions as references. However the captured motions may not be applied directly to the humanoid, since the differences in geometric or dynamics aspects as length, mass, degrees of freedom, and kinematics and dynamics capabilities exist between the humanoid and the human. To overcome this difficulty a method to adapt captured motions to a humanoid is developed. The geometric difference in the arm length is resolved by scaling the arm length of the humanoid with a constant. Using the scaled geometry of the humanoid the imitation of actor's arm motions is achieved by solving an inverse kinematics problem formulated using optimization. The errors between the captured trajectories of actor arms and the approximated trajectories of humanoid arms are minimized. Such dynamics capabilities of the joint motors as limits of joint position, velocity and acceleration are also imposed on the optimization problem. Two motions of one hand waiving and performing a statement in sign language are imitated by a humanoid through dynamics simulation.

• 제어로봇시스템학회:학술대회논문집
• /
• 1986.10a
• /
• pp.36-40
• /
• 1986

This paper describes a design of the dynamic robot arm controller with two points of view, robustness and minimum tracking error. A new approach to the robust control of robot arm is developed and an explicit solution for minimum tracking error control is obtained from the regulator problem in the error space given by modifying the tracking problem. This control law is applied to the SCARA robot and the computer simulation is presented.

• Proceedings of the KIEE Conference
• /
• 2007.07a
• /
• pp.1777-1778
• /
• 2007

In this paper, We design and implement a humanoid robot, With Educational purpose, which can collaborate and communicate with human. We present an affective human-robot communication system for a humanoid robot, D2, which we designed to communicate with a human through dialogue. D2 communicates with humans by understanding and expressing emotion using facial expressions, voice, gestures and posture. Interaction between a human and a robot is made possible through our affective communication framework. The framework enables a robot to catch the emotional status of the user and to respond appropriately. As a result, the robot can engage in a natural dialogue with a human. According to the aim to be interacted with a human for voice, gestures and posture, the developed Educational humanoid robot consists of upper body, two arms, wheeled mobile platform and control hardware including vision and speech capability and various control boards such as motion control boards, signal processing board proceeding several types of sensors. Using the Educational humanoid robot D2, we have presented the successful demonstrations which consist of manipulation task with two arms, tracking objects using the vision system, and communication with human by the emotional interface, the synthesized speeches, and the recognition of speech commands.

• Steel and Composite Structures
• /
• v.45 no.5
• /
• pp.697-713
• /
• 2022

In the context of the finite elements method, the dynamic behavior of porous functionally graded double wishbone vehicle suspension structural system incorporating joints flexibility constraints under road bump excitation is studied and analyzed. The functionally graded material properties distribution through the thickness direction is simulated by the power law including the porosity effect. To explore the porosity effects, both classical and adopted porosity models are considered based on even porosity distribution pattern. The dynamic equations of motion are derived based on the Hamiltonian principle. Closed forms of the inertia and material stiffness components are derived. Based on the plane frame isoparametric Timoshenko beam element, the dynamic finite elements equations are developed incorporating joint flexibilities constraints. The Newmark's implicit direct integration methodology is utilized to obtain the transient vibration time response under road bump excitation. The presented procedure is validated by comparing the computational model results with the available numerical solutions and an excellent agreement is observed. Obtained results show that the decrease of porosity percentage and material graduation tends to decrease the deflection as well as the resulting stresses of the control arms thus improving the dynamic performance and increasing the service lifetime of the control arms.

• 제어로봇시스템학회:학술대회논문집
• /
• 2003.10a
• /
• pp.1178-1183
• /
• 2003

As personal robots coexist with a person with a role to help a person, while adapting various human life and environment, the personal robots have to accommodate frequently-changing or different-from-home-to-home environment. In addition, personal robots may have many kinds of different Kinematic configurations depending on the capabilities. Some may have a mobile base and others may have arms and a head. The motivation of this study arises from this not-well-defined home environment and varying Kinematic configuration. So the goal of this study is to develop a general control architecture for personal robots. There exist three major architectures; deliberative, reactive and hybrid. We found that these are applicable only for the defined environment with a fixed Kinematic configuration. Neither could accommodate the above two requirements. For the general solution, we propose a Supervised Hybrid Architecture (SHA), in which we use double layers of deliberative and reactive controls, distributed control with a modular design of Kinematic configurations, and real-time Linux OS. Deliberative and reactive actions interact through a corresponding arbitrator. These arbitrators help a robot to choose an appropriate architecture depending on the current situation to successfully perform a given task. The distributed control modules communicate through IEEE 1394 for the easy expandability. With a personal robot platform with a mobile base, two arms, a head and a pan-tilt stereo eye system, we tested the developed SHA for static as well as dynamic environments. For this application, we developed decision-making rules for selecting appropriate control methods for several situations of navigation task. Examples are shown to show the effectiveness.

• 제어로봇시스템학회:학술대회논문집
• /
• 1989.10a
• /
• pp.200-205
• /
• 1989

The performance of conventional robot arms is inhibited by trade-off between speed and accuracy. Because these systems measure only joint angles, in spite of slow speed, they must rely on a stiff structure in order to attain positioning accuracy. Lightweight links would allow faster motion, but their flexibility would also produce positioning errors. This research is involved with the development and evaluation of an End-point Control System whose major goal is to compensate for link deflections and thus mitigate the speed versus accuracy conflict in conventional manipulator.