• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.66 no.6
• /
• pp.927-934
• /
• 2017

This paper is concerned with applicability of two-degree-of-freedom controllers to the recently suggested i-PID controllers, in which unknown parts of the plant are taken into account without any modeling procedure. First, i-PID controller with two-degree-of-freedom is applied to a specific model, called Anisochronic model, to confirm the usefulness of this method. Second, using the original examples of i-PID controllers, it is confirmed that performance/robustness of system are to be improved due to two-degree-of-freedom, especially when the input changes suddenly. It is seen that as the desired robustness increases the optimal value of two-degree-of-freedom parameter ${\alpha}_A$ would be negative. It is checked and verified that if this value was limited to 1 or less as is generally known, performance would be degraded.

• 제어로봇시스템학회:학술대회논문집
• /
• 1996.10b
• /
• pp.1304-1307
• /
• 1996

In this paper, we present a robust Two Degree of Freedom (TDF) $H_{\infty}$ controllers for a missile system. The feedback controller is designed to meet robust stability and disturbance rejection specifications while the prefilter is used to improve the robust model matching properties of the closed loop system. As the perturbed model, we use the normalized coprim factor perturbations. These controllers are designed using $H_{\infty}$ optimization procedures, and applied to a missile model via simulation.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.22 no.2
• /
• pp.467-475
• /
• 1998

The Six Degree-of-Freedom manipulators are generally operated by linear actuators which are hydraulic cylinder, pneumatic cylinder, ball-screw. But these actuators are not adequate to have a wide work-space, and furthermore some of them have a self-locking property. Therfore, we have designed a new manipulator which fully overcomes these demerits. The new manipulating system consists of 6 DC-motors to generate operation forces and 6 position transducers to feedback displacement signals. This paper presents an overview of the design and characteristics of 6 Degree-of-Freedom force feedback manipulators for vitual reality implementation. we can operate Six Degree-of-Freedom manipulator with six motors and six potentiometers.

• 제어로봇시스템학회:학술대회논문집
• /
• 1991.10a
• /
• pp.258-263
• /
• 1991

Optimal configurations for redundant TDOF (Two Degree Of Freedom) sensor systems are proposed. The determinant of error covariance matrix is used as the performance index, and optimal configurations for 2 TDOF sensor system and 3 TDOF sensor system are evaluated by minimizing the index.

• Proceedings of the Korea Institute of Convergence Signal Processing
• /
• 2000.12a
• /
• pp.193-196
• /
• 2000

ln this paper, we consider to apply of 2-DOF (Degree of Freedom) PID controller at D.C servo motor system. Many control system use I-PD, PIB control system. but the position control system have difficulty in controling variable load and changing parameter We propose neural network 2-DOF PID control system having feature for removal disturbrances and tracking function in the target value point.

• Journal of Advanced Marine Engineering and Technology
• /
• v.20 no.3
• /
• pp.110-120
• /
• 1996

The purpose of this study is to build up the control scheme that promptly controls the pressure in a hydraulic cylinder having small control volume, using a PCV(proportional control valve) and a digital computer. Object pressure control system has the character to be unstable easily, because the displacement-flow gain of the PCV is so large considering comparatively small volume of the hydraulic cylinder and the time delay of response of PCV is long. Considering the above-mentioned characteristics of the object pressure control system, in this study, a control system is designed with two degree of freedom scheme that is composed by adding a feed-forward control path to I-PD control system, and the reference model is used to decide control parameters. And through some experiments on FF-I-PD, the validity of this control method is confirmed.

• Journal of Advanced Marine Engineering and Technology
• /
• v.22 no.6
• /
• pp.888-893
• /
• 1998

In this paper, we present a magnetic levitation system which has not a gap sensor with sensor-less realization and stabilizing controller design. For measuring gap between magnet and levitated object we propose a gap sensorless method and adop two-degree-of-freedom controller for robust-ness and performence of the magnetic levitation system. From time responeses we confirm that the proposed sensorless method which can be applied to magnetic levitation system. Also the designed stabilizing controller has good disturbance rejection and reference tracking performance.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.12 no.2
• /
• pp.193-199
• /
• 1988

The forced vibrations of nondissipative nonlinear two-degree-of-freedom system, subjected to periodic forcing functions, are investigated by use of the method of slowly changing phase and amplitude. The first order differential equations are derived for nonrationally solutions and the coupled nonlinear algebraic equations for stationary solutions. Through investigating the response curves of the system, which are obtained numerically by using Newton-Raphson method, it is found that the resonances can occur at more than the number of degree-of-freedom of the system depending on the relation between the nonlinear spring parameters, which has no counterpart in linear systems.

• Proceedings of the KIEE Conference
• /
• 1995.07b
• /
• pp.670-672
• /
• 1995

This paper deals with the robust two-degree-of-freedom multivariable control system using $H_{2}/H{\infty}$optimization method which can achieve the robust stability and the robust performance, simultaneously. The feedback controller can obtain the robust stability property. The feedforward controller can obtain the robust performance property under modelling error. The robust two-degree-of-freedom multivariable control system is applied to the nonlinear multivariable boiler-turbine system. The validity of the proposed method is verified though being compared with LQG/LTR design method.

• Earthquakes and Structures
• /
• v.13 no.3
• /
• pp.231-239
• /
• 2017

Fundamental period is one of the most critical parameters affecting the seismic design of buildings. In this paper, a very simple approach is presented for estimating the fundamental period of multiple-degree-of-freedom (MDOF) structures. The basic idea behind this approach is to replace the complicated MDOF system with an equivalent single-degree-of-freedom (SDOF) system. To realize this equivalence, a procedure for replacing a two-degree-of-freedom (2-DOF) system with an SDOF system, known as a two-to-single (TTS) procedure, is developed first; then, using the TTS procedure successively, an MDOF system is replaced with an equivalent SDOF system. The proposed approach is expressed in terms of mass, stiffness, and number of stories, without mode shape or any other parameters; thus, it is a very simple method. The accuracy of the proposed method is investigated by estimating the fundamental periods of many MDOF models; it is found that the results obtained by the proposed method agree very well with those obtained by eigenvalue analysis.