• Journal of Institute of Control, Robotics and Systems
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• v.6 no.5
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• pp.356-366
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• 2000

In this paper, a nonlinear $H_2/H_\infty/LTR$ control for the flexible inverted pendulum of a parallel type with Coulomb friction is presented. The dynamic equation for this system is derived by the Hamilton's principle and assumed-mode method. This hard nonlinear system can be modeled by a the quasi-linear state space model using the REF method. It is shown that the $H_2/H_\infty$ control can be applied to the nonlinear controller design of the system having Coulomb frictions if the proper LTR conditions are satisfied. In order to present the usefulness of the suggested control method, the nonlinear $H_2/H_\infty/LTR$ controller is designed to control the Position of the end point of the flexible inverted pendulum that has Coulomb frictions present in actuator parts. The results are given via computer simulations.

• Journal of Drive and Control
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• v.10 no.3
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• pp.21-26
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• 2013

This paper presents a robust motion tracking control of a cylinder-toggle servomechanism for injection molding machines. Virtual design model has been developed for a five-point type toggle mechanism. A sliding function is defined and combined with PID control to accommodate mismatches between the real plant and the linear model used. From tracking control simulations, it is shown that significant reduction in position tracking error is achieved with clamping force build-up through the use of proposed control scheme.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.1
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• pp.99-107
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• 2014

In this paper, a landmark based localization system using a Kinect sensor is proposed and evaluated with the implemented system for precise and autonomous navigation of low cost robots. The proposed localization method finds the positions of landmark on the image plane and the depth value using color and depth images. The coordinates transforms are defined using the depth value. Using coordinate transformation, the position in the image plane is transformed to the position in the body frame. The ranges between the landmarks and the Kinect sensor are the norm of the landmark positions in body frame. The Kinect sensor position is computed using the tri-lateral whose inputs are the ranges and the known landmark positions. In addition, a new matching method using the pin hole model is proposed to reduce the mismatch between depth and color images. Furthermore, a height error compensation method using the relationship between the body frame and real world coordinates is proposed to reduce the effect of wrong leveling. The error analysis are also given to find out the effect of focal length, principal point and depth value to the range. The experiments using 2D bar code with the implemented system show that the position with less than 3cm error is obtained in enclosed space($3,500mm{\times}3,000mm{\times}2,500mm$).

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.4
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• pp.363-370
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• 2014

A new NURBS-based shape optimization method is proposed. Most shape optimization studies consider only control point positions as design variables. Some shape optimization processes present problems with mesh quality and convergence when control points are constrained to a limited space. If the weights of the control points are regarded as additional design variables, it should be possible to attain a better degree of shape control. In this study, positions and weights of NURBS control points are used as design variables, and a shape optimization algorithm incorporates position optimization and weight optimization steps. This method is applied to shape optimization benchmarking problems to verify its advantages.

• Journal of Korean Institute of Industrial Engineers
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• v.38 no.1
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• pp.41-45
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• 2012

Until now, most studies of foot moving or driving posture have been performed under laboratory driving conditions. But there are many different things between actual driving conditions and laboratory driving conditions because, in laboratory conditions, it is hard to consider vehicle's noise, vibration and people's psychology state while driving. Thus this study is performed through actual driving conditions. And while driving test, we recorded driver's foots with 2 cameras to investigate foots(left and right) heel point and how human foots move to control the three pedals : accel, brake and footrest.. Through driving test, the results of this study show that the position of driver's heel point isn't related to stature and tends to be generalized.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10a
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• pp.113-118
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• 1993

This paper represents mechanical compliance & ZMP(Zero Moment Point) control algorithm for IWR(Inha Walking Robot) system. In case of walking in different environments, a biped walking robot must vary its gait(walking period or step length, etc.) according to the environments. However, most of biped walking robots do not have the capability to change their gaits or need more complex control algorithm, because ZMP cannot be defined in their control algorithm. Therefore new linear type with balancing joint is proposed which is used as an aid in balancing & ZMP control itself. In IWR system, ZMP can be defined by solving differential equations and it does not need to be predefined ZMP trajectory. Furthermore we can input the desired ZMP position. In parallel with the development, we also considered a mechanical compliance for reducing the inverse kinematics, dynamics and the control complexity. It will figure out some powerful adaptation with 3D irregular terrains.

• 제어로봇시스템학회:학술대회논문집
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• 1992.10a
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• pp.993-998
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• 1992

The paper treated the oscillation control of cargo rope and the position control of cart for a tower crane system by adopting the optimal regulator method. Since the tower crane has nonlinearity and it is very unstable when the cargo is mobiling, an insensitive control system with respect to oscillation of cargo rope and disturbance such as wind is required. In this paper, model equation of the tower crane is induced by using Lagrange equation and it is linearized at equilibrium point. The real time control of tower crane syste is implemented by 16bits microcomputer with A/D and D/A convetters to illustrate the application of the adopted optimal desgn method.

• Journal of Aerospace System Engineering
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• v.6 no.3
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• pp.24-28
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• 2012

An actuator should be added to a existing control linkage to make manned aircraft to unmanned. But it is quiet difficult to synchronize actuator with control surface because non-linear error necessarily occurs when four-bar linkage acts in three dimensional motion. In addition, in point of controller design view, while a real-time model needs the control surface deflection as its input, controller needs the actuator command as its output. Hence, the relation between both should be investigated. In this paper, the mathematical relation between actuator and control surface deflection investigated by kinematic analysis of a plant aircraft. The performance margin of the selected actuator also was verified.

• Proceedings of the KIEE Conference
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• 1995.07b
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• pp.830-832
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• 1995

A position Control algorithm of the flexible manipulator is studied. The proposed algorithm is based on a Fuzzy Logic Control(FLC) method using the human's experiences. FLC does not need a dynamic modeling of a flexible manipulator. A Fuzzy logic controller is designed that the end-point of the flexible manipulator tracks the desired trajectory. The control input to the process is determined by the error and variation of error. Simulation result shows a robustness of FLC compared with the PID control algorithm.

• Journal of the Korean Society of Safety
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• v.8 no.4
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• pp.213-222
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• 1993

This paper is concerned with automation of tower cranes in view of the robust control of tower crane during take-off, load hoisting, load lowering and landing. The model equation of the tower crane is induced by using Lagrange's equation and it is linearized at equillibrium point. The control is realized by adopting the optimal regulator method. The effectiveness is proved through the experimental results for the oscillation control of cargo rope and the position controls of trolley and boom by the implementation of digital control using 16 bits microcomputer for the designed optimal control law.