• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.425-425
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• 2000

The heavy duty power manipulate generally has high ratio gear reducers at its joints. When it is used as a slave manipulator in the teleoperation system, therefore, the control input saturates frequently and its tracking performance and stability ate also likely to be deteriorated. This paper proposes a force reflecting control scheme for the manipulator with control input saturation. A series of experiments are shown to give excellent tracking performance with force reflection regardless of control input saturation.

• Smart Structures and Systems
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• v.8 no.2
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• pp.157-172
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• 2011

A new method for both local damage(s) identification and input excitation force identification of beam structures is presented using the dynamic response sensitivity-based finite element model updating method. The state-space approach is used to calculate both the structural dynamic responses and the responses sensitivities with respect to structural physical parameters such as elemental flexural rigidity and with respect to the force parameters as well. The sensitivities of displacement and acceleration responses with respect to structural physical parameters are calculated in time domain and compared to those by using Newmark method in the forward analysis. In the inverse analysis, both the input excitation force and the local damage are identified from only several acceleration measurements. Local damages and the input excitation force are identified in a gradient-based model updating method based on dynamic response sensitivity. Both computation simulations and the laboratory work illustrate the effectiveness and robustness of the proposed method.

• Structural Engineering and Mechanics
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• v.34 no.1
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• pp.1-14
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• 2010

The innovative intelligent fuzzy weighted input estimation method which efficiently and robustly estimates the unknown time-varying input force in on-line is presented in this paper. The algorithm includes the Kalman Filter (KF) and the recursive least square estimator (RLSE), which is weighted by the fuzzy weighting factor proposed based on the fuzzy logic inference system. To directly synthesize the Kalman filter with the estimator, this work presents an efficient robust forgetting zone, which is capable of providing a reasonable compromise between the tracking capability and the flexibility against noises. The capability of this inverse method are demonstrated in the input force estimation cases of the plate structure system. The proposed algorithm is further compared by alternating between the constant and adaptive weighting factors. The results show that this method has the properties of faster convergence in the initial response, better target tracking capability, and more effective noise and measurement bias reduction.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.10a
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• pp.671-677
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• 2009

A reaction wheel is commonly used, as an important actuator, to control the attitude of a satellite. Operation of the reaction wheel plays a role of an excitation source to loading equipment inside the satellite. As requirements for environmental vibration to manifest the performance of precision equipment are getting more stringent, the research for analysis or reduction of unwanted action force in high frequency range when operating the reaction wheel is necessary. In this paper, the procedure to extract input forces and damping of a rotor system of reaction wheel is suggested. The analysis for measured action forces of reaction wheel is accomplished and important higher harmonics of action forces are determined. The input forces and damping of the rotor system are, then, extracted by curve-fitting and a particular solution for input force.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.49 no.10
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• pp.572-581
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• 2000

When the manipulator consisting of high ratio gear reducers at its joints is used as the slave manipulator in teleoperated systems, its dynamic characteristics is much slower than that of the master manipulator and it is likely to encounter the saturation in the input magnitude. The control input saturation generates an windup phenomenon that the system stability and position tracking performance of the slave manipulator are to be deteriorated. This paper proposes an force reflecting control scheme and its design method which compensates the control input saturation with absolute stability. The proposed scheme is shown to give a stable force reflection while compensating for control input saturation effectively.

• 제어로봇시스템학회:학술대회논문집
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• 1992.10a
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• pp.652-657
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• 1992

This paper presents to accomplish successfully a multi-input real time control by applying control hierarchy for sliding mode of multi-joint manipulators whose nonlinear terms are regarded as disturbances. We- could simplify the dynamic equations of a manipulator and servo system, which are composed of linear elements and nonlinear elements, by assuming that nonlinear terms, which are Inertia term, gravity force term, Coriolis force term and centrifugal force term, are external disturbance. By simplifying that equation, we could easily obtain a control input which satisfy sliding mode of multi-input system. We proposed a new control input algorithm in order to decrease chattering by changing control input according as effect of disturbance if a control response become within allowance error range. In this experiments, we used DSP(Digital Signal Processor) controller to suppress chattering by time delay of calculation and to carry out real time control.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.20 no.3
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• pp.263-271
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• 2010

A reaction wheel is commonly used, as an important actuator, to control the attitude of a satellite. Operation of the reaction wheel plays a role of an excitation source to loading equipment inside the satellite. As requirements for environmental vibration to manifest the performance of precision equipment are getting more stringent, the research for analysis or reduction of unwanted action force in high frequency range when operating the reaction wheel is necessary. In this paper, the procedure to extract input forces and damping of a rotor system of reaction wheel is suggested. The analysis for measured action forces of reaction wheel is accomplished and important higher harmonics of action forces are determined. The input forces and damping of the rotor system are, then, extracted by curve-fitting and a particular solution for input force.

• Transactions on Electrical and Electronic Materials
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• v.10 no.5
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• pp.156-160
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• 2009

In an ultrasonic motor, a piezoelectric ceramic material forms the active element which vibrates the stator, thus initiating the rotational motion. In the operation of ultrasonic motors, many factors exist that can affect the resonance characteristics of the piezoelectric ceramic component. For examples, these factors are the bonding conditions with the piezoelectric element, the magnitude of the input voltage, the normal force in the frictional drive and the emission of heat due to vibration and friction etc. Therefore, it is important to research properly the inclination for variation of piezoelectric ceramics in the circumstance where complex elements are involved. In this paper, we focus on the analysis of the resonance characteristics of an ultrasonic motor as a function of the magnitude of the input voltage and the normal force.

• Journal of Industrial Technology
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• v.19
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• pp.173-178
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• 1999

In many areas of technology there are machines and systems controllable in up to six degrees of freedom. Helicopters and underwater vehicles, industrial robots are among the first representatives of this category. They need six degrees of freedom in order to move and orient within their workspace. An even broader and more explosively growing area is 3D computer graphics and virtual environment. In this work, functions of 3D input device are described and two types of commercial 3D input device are presented. Then, a preliminary experiment of a low cost 6 axis force/moment sensor is presented that can also be sued as a 3D input device. A low cost force/moment sensor and its application in robot teaching experiment is described. It computes the direction of 3 components of the force and 3 components of the moment applied by human holding the sensor by hand. The concept is shown by an experiment where the tool position and orientation of a robot in 3 dimensional space is controlled by the proposed sensor.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.04b
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• pp.246-250
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• 1995

This paper presents a method in analyzing the output force/moments transmission form the applied input forces of the paralled manipulator. Like a serial manipulator the Jacobian matrix introduced in the paper plays role in relating the output forces/monents with the input forces. The force/moment manipulability have been investigated by considering the force transmission and momen transmission independently. Sensitivity analysis has been done and an illuatrating example is given.