• Journal of Advanced Marine Engineering and Technology
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• v.26 no.5
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• pp.581-588
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• 2002

A fuzzy learning control algorithm is proposed in this paper. In this method, two fuzzy controllers are used as a feedback and a feedforward type. The fuzzy feedback controller can be designed using simple knowledge for the controlled system. On the other hand, the fuzzy feedforward controller has a self-organizing mechanism and therefore, it does not need any knowledge in advance. The effectiveness of the proposed algorithm is demonstrated by experiment on the position and force control problem of a parallelogram type robot manipulator with two degrees of freedom. It is shown that the rapid learning and the robustness can be achieved by adopting the proposed method.

• Earthquakes and Structures
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• v.10 no.5
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• pp.1067-1087
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• 2016

In this paper, a decoupled proportional-integral-derivative (PID) control approach for seismic control of smart structures is presented. First, the state space equation of a structure is transformed into modal coordinates and parameters of the modal PID control are separately designed in a reduced modal space. Then, the feedback gain matrix of the controller is obtained based on the contribution of modal responses to the structural responses. The performance of the controller is investigated to adjust control force of piezoelectric friction dampers (PFDs) in a benchmark base isolated building. In order to tune the modal feedback gain of the controller, a suitable trade-off among the conflicting objectives, i.e., the reduction of maximum modal base displacement and the maximum modal floor acceleration of the smart base isolated structure, as well as the maximum modal control force, is created using a multi-objective cuckoo search (MOCS) algorithm. In terms of reduction of maximum base displacement and story acceleration, numerical simulations show that the proposed method performs better than other reported controllers in the literature. Moreover, simulation results show that the PFDs are able to efficiently dissipate the input excitation energy and reduce the damage energy of the structure. Overall, the proposed control strategy provides a simple strategy to tune the control forces and reduces the number of sensors of the control system to the number of controlled stories.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.871-875
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• 1996

The Output feedback linear quadratic regulator control is applied to the design of active suspension system using 7 DOF full car model. The performance index reflects the vehicle vertical movement, pitch and roll motion, and minimization of suspension stroke displacements in the rattle space. The elements of gain matrix are approximately decoupled so that each suspension requires only local information to generate the control force. The simulation results indicates that the output feedback LQ controller is more effective than purely passive or full state feedback active LQ controllers in following the road profile at the low frequency range and suppressing the road disturbance at the high frequency ranges.

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

• Journal of the Korean Society for Precision Engineering
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• v.16 no.1 s.94
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• pp.42-48
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• 1999

A control method for a robot hand grasping a object in a partially unknown environment will be proposed, where a proximate sensor detecting the distance between the fingertip and object was used. Particularly, the finger joints were driven servo-pneumatically in this study. Based on the proximate sensor signal the finger motion controller could plan the grasping process divided in three phases ; fast aproach, slow transitional contact and contact force control. That is, the fingertip approached to the object with full speed, until the output signal of the proximate sensor began to change. Within the perating range of the proximate sensor, the finger joint was moved by a state-variable feedback position controller in order to obtain a smooth contact with the object. The contact force of fingertip was then controlled using the blocked-line pressure sensitivity of the flow control servovalve for finger joint control. In this way, the grasping impact could be reduced without reducing the object approaching speed. The performance of the proposed grasping method was experimentally compared with that of a open loop-controlled one.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.19 no.3
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• pp.288-293
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• 2009

This study presents the active noise control of duct noise. The duct was excited by a steady-state harmonic and white noise force and the control was performed by one control speaker attached to surface of the duct. An adaptive controller based on filtered x LMS(FXLMS) algorithm was used and controller was defined by minimizing the square of the response of the error microphone. The assemble controller, which is called a hybrid ANC(active noise control) system, was combined with feedforward and feedback controller. The feedforward ANC attenuates primary noise that is correlated with the reference signal, while the feedback ANC cancels the narrowband components of the primary noise that are not observed by the reference sensor. Furthermore, in many ANC applications, the periodic components of noise are the most intense and the feedback ANC system has the effect of reducing the spectral peaks of the primary noise, thus easing the burden of the feedforward ANC filter.

• 제어로봇시스템학회:학술대회논문집
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• 1987.10a
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• pp.892-897
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• 1987

The ability of a robotic manipulator to recognize the shape of an object by feeling its band around the object is useful in many applications. Two-dimensional object contour tracking by force feedback is described. The system consists of IBM PC/AT, PUMA 560 manipulator, PUMA controller and a tip sensor. Position control is accomplished by using VAL command and the unmodified PUMA controller. A contour tracking algorithm is developed and tested on three different types of objects. The experimental results show that the objects' shapes can be successfully identified.

• The Journal of Korea Robotics Society
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• v.12 no.3
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• pp.356-364
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• 2017

This paper presents a force control based on the observer without taking any force or torque measurement from the robot which allows realizing more stable and robust human robot interaction for the developed multi-functional upper limb rehabilitation robot. The robot has four functional training modes which can be classified by the human robot interaction types: passive, active, assistive, and resistive mode. The proposed observer consists of internal disturbance observer and external force observer for distinctive performance evaluation. Since four training modes can be quantitatively identified as impedance variation, position-based impedance control with feedback and feedforward controller was applied to the assistive training mode. The results showed that the proposed sensorless observer estimated cleaner and more accurate force compared to the force sensor and the impedance controller embedded with the proposed observer completed the assistive training mode safely and properly.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2001.05a
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• pp.42-47
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• 2001

가상현실 기술은 이제 컴퓨터가 생성한 환경과 사용자간의 자유로운 상호작용을 수행할 수 있도록 하는 것이 중요하게 되었다. 이러한 상호작용을 위해서는 시각 제시기뿐만 아니라 사용자가 가상환경에서 물리적인 힘을 느낄 수 있도록 하는 것이 중요하다. 본 논문은 가상환경에서 사용자에게 운동감을 제시할 수 있는 기기들의 소프트웨어적인 아키텍처를 제안하고, 또한 이러한 기기들을 연결하는 데 있어서 가상환경과 통합될 수 있도록 가상환경 서보와 힘 피드백 제시기간의 통신규약을 제시한다.

• Journal of Institute of Control, Robotics and Systems
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• v.9 no.2
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• pp.124-130
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• 2003

The electro-hydraulic servo system with a servo valve is applied widely in force control. However, the composition of control system using a servo valve is difficult due to nonlinearities in the servo valve, such as square-root terms in flow equation. The electro-hydraulic servo system using a DDV(Direct Drive Valve) instead of a servo valve was proposed and it's characteristics was estimated. The DDV and whole system are modelled by parameter identification using the input-and-output data, then the models are verified by the comparison of simulation with experiment. Also, the state feedback controller has been designed based on this model, then the performance of the electro-hydraulic force servo system using a DDV is evaluated by simulation and experimental results.