• Journal of Institute of Control, Robotics and Systems
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• v.14 no.8
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• pp.842-847
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• 2008

This paper proposes a new sliding-surface-based tracking control system for nonholonomic mobile robots with disturbance. To design a robust controller, we consider the kinematic model and the dynamic model of mobile robots with disturbance. We also propose a new sliding surface to solve the problem of previous study. That is, since the new sliding surface is composed of differentiable functions unlike the previous study, we can obtain the control law for arbitrary trajectories without any constraints. From the Lyapunov stability theory, we prove that the position tracking errors and the heading direction error converge to zero. Finally, we perform the computer simulations to demonstrate the performance of the proposed control system.

• Proceedings of the KIEE Conference
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• 2001.11c
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• pp.57-60
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• 2001

In the distributed control systems where the control components, controllers and sensors are distributed on a communications network, there exit network time delays on communication lines between the system components. This paper deals with the 2 D.O.F. ramp tracking controller design issue for such system. Time delay terms are converted into rational terms using Pade approximation method and the system is augmented with two integrators for ramp tracking. For this system, $\mu$-controller design method, which enables to meet not only performance requirements but robust stabilities simultaneously, is employed.

• Proceedings of the KIEE Conference
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• 1999.07b
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• pp.951-953
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• 1999

In the distributed control systems where the control components, controllers and sensors are distributed on a communications network, there exist network time delays on communication lines between the system components. This paper deals with the ramp tracking controller design issue for such systems. Time delay terms are converted into the rational terms using Pade approximation method and the system is augmented with two integrators for ramp tracking. For this system, ${\mu}$-controller design method, which enables to meet not only performance requirements but robust stabilities simultaneously, is employed.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.496-499
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• 1997

Field robot represented by excavator can be applied for various kinds of working in manufacturing, construction, agriculture etc. because of the flexibility of its multi-joint mechanism and the high power of hydraulic actuators. In general, the dynamics of field robot have strong coupling, various kinds of non-linearity, and time-varying parameters according to working conditions. Therefore, it is very difficult to describe the system well, and design controller systematically based on its model. This paper established the mathematical model of field robot driven by electro-hydraulic servomechanism and constructed the adaptive control system robust to external load variations. The proposed control system for the field robot was evaluated by the computer simulation and the performance results of trajectory tracking were compared with that of PID control system.

• 제어로봇시스템학회:학술대회논문집
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• 1987.10b
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• pp.41-46
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• 1987

A new control scheme is developed to achieve fast and accurate decoupled tracking for an n-Joint robotic manipulator In the Presence of disturbances and unknown Parameter variations. The control system is designed so that a new type of state trajectories called sliding mode may exist in a phase plane. In order to remove the reaching Phase and high frequency chattering phenomenon which ate the common shortcomings of variable structure control(VSC) scheme, this paper presents the new switching line which is composed of three segments and the continuous control law which is derived from the existence condition of a sliding mode. The Proposed methods in this Paper are applied to a 3-Joint robotic manipulator as a numerical example-The digital simulation results which are compared with those of typical VSC scheme show the validity of accurate tracking capability and robust Performance of the system.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.01a
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• pp.174-177
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• 2009

In object tracking, the template matching methods have been developed and frequently used. It is fast enough, but not robust to an object with the variation of size and shape. In order to overcome the limitation of the template matching method, this paper proposes a template update technique. After finding an object position using the correlation-based adaptive predictive search, the proposed method selects blocks which contain object's boundary. It estimates the motion of boundary using block matching, and then updates template. We applied it to IR image sequences including an approaching object. From the experimental results, the proposed method showed successful performance to track object.

• Proceedings of the KIEE Conference
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• 2000.07d
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• pp.3031-3033
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• 2000

Surveillance system on the internet has attained lots of interests recently. Computer gives surveillance system various functions like remote control and motion detecting. In this paper. auto target tracking system using Pan/Tilt camera is suggested. It consists of UNIX server and Pan/Tilt camera. When UNIX server detect motions from images it sends Pan/Tilt command to camera and camera moves by command. After finishing movement camera replies to server and server starts detecting motion again. To improve performance of motion detecting and tracking images are divided into 9 sub-regions and camera behaves differently. It is certain that robust tracking is achieved when sub-region is applied.

• Proceedings of the KIEE Conference
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• 1999.07g
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• pp.2989-2991
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• 1999

We design the stable controller with variable gains and reference velocity in order to apply to this controller the proper gains and reference velocity generated with fuzzy logic in on-line. The proposed controller is applied to solve two problems including the reference velocity tracking problem and speedy tracking problem. The result of the simulation show a robust performance under the different conditions

• Transactions of The Korea Fluid Power Systems Society
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• v.3 no.2
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• pp.14-20
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• 2006

A controller design procedure for an electro-hydraulic positioning systems has been developed using $H{\infty}$ control. The generalized plant models and weighting function for multiplicative uncertainty modelling error was presented along with $H{\infty}$ controller designs in order to investigate the robust stability and performance. Both disturbance rejection and command tracking performances were improved with the $H{\infty}$ controller, and the better uniformity of time response is achieved across wide range of operating conditions than the PID, LQR and LQG control scheme. The multiplicative uncertainty case was specifically suited for the design of an electro-hydraulic positioning control systems using $H{\infty}$ control.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.4
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• pp.365-371
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• 2012

This paper presents robust control performance of a direct current(DC) motor with brake system adopting a giant electrorheological(GER) fluid, whose distinguished feature is an extremely high value of yield stress. As a first step, Bingham characteristics of the GER fluid is experimentally investigated using the Couette type electroviscometer. A cylindrical type of ER brake is then devised based on the Bingham model, and its braking torque is evaluated. Structural analysis of ER break is performed using ANSYS. After formulating the governing equation of motion for the DC motor with ER brake system, a sliding mode control algorithm, which is very robust to external disturbances and parameter uncertainties, is synthesized and experimentally realized in order to achieve desired rotational speed trajectories. The tracking responses of the control system are then evaluated and verified by presenting speed control performance.