• Proceedings of the KSME Conference
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• 2003.04a
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• pp.799-804
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• 2003

Friction phenomenon can be described as two parts which are pre-sliding and sliding regions. In motion of the sliding region, friction forces depend on the velocity of the system and are known as Coulomb, stick-slip, stribeck effect and viscous friction. The pre-sliding region, which is before breakaway, depends on the position of the system. The motion of friction in the sliding region can be described as the LuGre model. But the pre-sliding motion of friction, which has hysteresis characteristics in general, is not known widely. Therefore, an improved friction model, which can describe the motion of friction in the pre-sliding region, is proposed in this paper. And simulation and experimental results show the effectiveness of the proposed friction model for precise tracking control systems.

• Proceedings of the KIEE Conference
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• 2000.07d
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• pp.2290-2292
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• 2000

Robustness characteristics to the modelling imprecision and some disturbances could be achieved in sliding mode control. However, there are drawbacks such as discontinuous control and chattering. Recently, many researches have been developing to solve such the problems. In sliding mode control, overall control input could be divided into two parts which are equivalent control input and sliding mode control input. Sliding mode control input is a function of the switching surfaces and can be designed with their linear combinations. In this paper, the sliding mode control input is designed by TSK fuzzy model. The proposed method gives the continuous sliding control input and reject the chattering phenomenon.

• Journal of Institute of Control, Robotics and Systems
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• v.8 no.2
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• pp.89-96
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• 2002

A new chattering free PD-sliding mode hybrid control scheme is proposed for robot manipulators. This hybrid controller is composed of a PD controller and a semi-continuous sliding mode controller. It has a good robust performance in reaching mode which does not possess invariance property of sliding mode, and has chattering free characteristics in sliding mode. Thus, the PD-sliding mode hybrid controller has a good robust performance in the whole region. It is shown that the proposed control has a good transient response and trajectory tracking performance for a 2-link SCARA robot manipulator.

• Journal of Korean Association for Spatial Structures
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• v.22 no.1
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• pp.67-73
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• 2022

Middle size of membrane retractable roof is under 25m span which consists of various moving systems. Sliding carriage is the system that leads the membrane to parking place, transferring the load from the membrane to structural cable. When membrane moves roof, thus, structural behavior of sliding carriage, which may contain various shapes with friction coefficients, should be investigated by vertical load as well as horizontal load. Nummerical simulation of sliding carriage prototypes, in this research, were performed by incrementation of vertical load and horizontal load as well. Consequently, this paper evaluated proper shapes of inner holder of Sliding carriage and evaluated the effective contact area of inner hold.

• Journal of Ocean Engineering and Technology
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• v.17 no.1
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• pp.55-60
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• 2003

The effect of size and volume fraction of ceramic particles, with sliding velocity on the wear properties were investigated for the metal matrix composites fabricated by the pressureless infiltration process. The metal matrix composites exhibited about 5.5 - 6 times the wear resistance compared with AC8A alloy at high sliding velocity, and by increasing the particle size and decreasing the volume fraction, the wear resistance was improved. The wear resistance of metal matrix composites and AC8A alloy exhibited different aspects. Wear loss of AC8A alloy increased with sliding velocity, linearly : whereas, metal matrix composites indicated more wear loss than AC8A alloy at the slow velocity region. However, a transition point of wear loss was found at the middle velocity region, which shows the minimum wear loss. Further, wear loss at the high velocity region exhibited nearly the same value as the slow velocity region. In terms of wear mechanism, the metal matrix composites generally exhibited abrasive wear at slow to high sliding velocity； however, AC8A alloy showed abrasive wear at low sliding velocity and adhesive and melt wear at high sliding velocity.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2002.10a
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• pp.379-384
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• 2002

The effect of size and volume fraction of ceramic particles with sliding velocity on the wear properties were investigated for the metal matrix composites fabricated by pressureless infiltration process. The particulate metal matrix composites exhibited about 5.5 - 6 times of excellent wear resistance compared with AC8A alloy at high sliding velocity, and as increasing the particle size and decreasing the volume fraction the wear resistance was improved. The wear resistance of metal matrix composites and AC8A alloy exhibited different aspects. Wear loss of AC8A alloy increased with sliding velocity linearly. whereas metal matrix composites indicated more wear loss than AC8A alloy at slow velocity region, however a transition point of wear loss was found at middle velocity region which show the minimum wear loss, and wear loss at high velocity region exhibited nearly same value with slow velocity region. In terms of wear mechanism, the metal matrix composites exhibited the abrasive wear at slow to high sliding velocity generally, however AC8A alloy showed abrasive wear at low sliding velocity and adhesive and melt wear at high sliding velocity.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.684-688
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• 1996

In this paper, to overcome drawbacks of variable structure control system a self-tuning fuzzy sliding mode control algorithm using gradient descent method is proposed. The proposed method has the characteristics which are viewed in conventional VSC, e.g. insensitivity to a class of disturbance, parameter variations and uncertainties in the sliding mode. To demonstrate its performance, the proposed control algorithm is applied to a one-degree of freedom robot arm. The results show that both alleviation of chattering and performance are achieved.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2003.09a
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• pp.419-426
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• 2003

An efficient procedure using LQR method for determining optimal sliding surfaces appropriate for different controller types is provided. The parametric evaluation of the dynamic characteristics of sliding surfaces is peformed in terms of SMC controller performance of single-degree-of-freedom(SDOF) systems. The control force limit is considered in this procedure. Numerical simulations for multi-degree-of-freedom(MDOF) systems verify the effectiveness of proposed method.

• Journal of Convergence Society for SMB
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• v.4 no.2
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• pp.25-31
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• 2014

Sliding mode design and analysis for nonlinear system was carried out. A designer will determine the parameters to know about the performance and robustness of the system dynamics. To investigate the characteristics of sliding mode control, an inverted pendulum model is applied by the sliding mode control and the state concerned is output. Comparison is made by evaluating different initial conditions, sliding numerical components for sliding surface, and input gain, the dynamic of output will be investigated to conclude the generality. Control approaches have their limitations and sliding mode control is no exception. The chattering problem is its main negative effect to overcome. This effect is displayed and in this project chattering problem is suppressed by a modified discontinuous controller.

• KSTLE International Journal
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• v.4 no.1
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• pp.27-30
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• 2003

The basic principles of tribo-systems and study method based on tribe-systems are introduced in the paper, Based on the viewpoint of tribe-systems, the experiment on tribology characteristics of friction lining material in multi-rope friction hoist is carried out. The research result shows: tribology characteristics of friction material are not its inherent characteristic but system characteristics of the tribo-systems, the“sliding-rope”of multi-rope friction hoist can be divided into“safety sliding-rope”and“fault sliding-rope”, study on friction material only based on characteristic of system where friction material exists possesses practical significance.