• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.50.2-50
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• 2001

Optimal control problems are notoriously difficult to solve either analytically or numerically except for limited cases of having simple dynamics. Evolutionary programming is a promising method of solving various optimal control problem arising in practice since it does not require the expression of Lagrange´s adjoint system and that it can easily implement the inequality constraints on the control variable, In this paper, evolutionary programming is combined with spline method, so the smoother control profile and the Jumping times could be obtained. The optimal profiles obtained by the proposed method are compared with exact solution if it is available. With more complicated model equation, the proposed method showed better performance than other researchers´. It is demonstrated that the evolutionary programming with spline method can ...

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.67.3-67
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• 2001

A fuzzy control strategy is described which is utilized to control the joint angle and tip deflection in single flexible manipulator. In this paper, an existing model for a single flexible manipulator is used f3r the initial development of an FLC. One FLC is designed to govern the joint angle of the manipulator as it is rotated from one position to another, and a second FLC is designed to attenuate the tip deflection which result from joint angle body motion. Reference Trajectory Command is an important method to reduce vibration in flexible beam. This paper presents a very simple command control shaping which eliminates multiple mode residual vibration in a flexible beam combined fuzzy controller ...

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.110-110
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• 2001

By the state transformation including independent outputs functions, a nonlinear process model can be decomposed into two subsystems; the one(design model) is described in output variables as new states and used for control system synthesis and the other(disturbance model) is described in the original unavailable states and its couplings with the design model are treated as uncertain time-varying parameters in the design model. Its existence with respect to the design model is ignored. So, the design model is and uncertain time-variant system. Control synthesis based on a reduced design model is a combined form of a time-variant input-output linearization with parameter estimation. The parameter estimation is also based on the design model and it gives the parameter estimates such that the estimated outputs follow the actual outputs in a specified way. The disturbances form disturbance model and as well all the other uncertainties affecting the outputs will be reflected into the estimated parameters used in the linearizing control law.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.170.2-170
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• 2001

In this paper, the dynamic system modeling and the state sensitivity analysis of the spin-coater system for the reduction of the vibration are proposed. In the respect of modeling, the spin-coater system is composed of components of servomotor, belt, spindle, and a supported base. Each component is defined and combined modeling is derived to 3dimensional equations. Verification of modeling is verified by experimental values of actual system in the frequency domain. By direct differentiation the constraint equations with respect to kinematic design variables, such as eccentricity of spindle, moment of inertia, torsional stiffness and damping of supported base, sensitivity equations are derived to the verified state equations. Sensitivity of design variables could be used for vibration reduction and natural frequency shift in the frequency domain. Finally, dominant design variables ...

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.162.5-162
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• 2001

This paper presents a indirect vector control system for induction motors using an adaptive fuzzy logic(AFL) speed estimator. The proposed speed estimator is based on the MRAS(Mode Referece Adaptive System) scheme. In general, the MRAS speed estimation approaches are more simple than any other strategies. However, there are some difficulties in the scheme, which are strong sensitivity to the motor parameters variations and necessity to detune the estimator gains caused by different speed area. In this paper, the AFL speed estimator is proposed to solve the problems. The structure of the proposed AFL is very simple. The input of the AFL is the rotor flux error difference between reference and adjustable model, and the output is the estimated incremental rotor speed. Moreover, the back propagation algorithm is combined to adjust the parameters of the fuzzy logic to the most appropriate values during the operating the system. Finally, the validity of the ...

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.155.4-155
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• 2001

This paper deals with the inertia property-based redundancy resolution in posture control of a mobile manipulator. As a measure for the redundancy resolution of a mobile manipulator, an effective inertia at the end effector in the operational space is proposed and investigated. The reduced effective inertia has a significant effect on reducing the impulse force in collision with environment. To find a posture satisfying both the reduced inertia and joint limit constraints, we propose a combined potential function method that can deal with multiple constraints. The proposed reduced inertia property algorithm is integrated into a damping controller to reduce the impulse force at collision and to regulate the contact force in mobile manipulation ...

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.147.5-147
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• 2001

This paper describes a gait algorithm and a velocity limitation method for a Leg-Wheel Robot. The gait algorithm enables the robot to preserve continuous locomotion even if the velocity command varies extensively. The velocity limitation method restricts the commanded velocity when it exceeds the mechanical limitation of the robot. Combined use of the velocity limitation method with the gait algorithm ensures the continuity of locomotion, and makes the gait pattern efficient with a long step length and low frequency of leg phase change. These methods can be applied to locomotion on unexplored rough terrain even if the range of roughness is unknown.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10a
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• pp.468-468
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• 1991

The variable-frequency type water supply equipment, which adopts the variable-voltage and variable-frequency converter(VVVF converter) to govern automatically the rotating speed of a pump, can save 15-20% of power, as compared with a throttle-controlled pump device or an airpressurized water supply equipment, and is finding a wide application. However, it still has some disadvantages : greater pressure fluctuations during switching over the pump and prolonged low-effeciency running of the pump in the case of small consumption of water. Therefore, it is difficult to apply the equipment to the fire water supply system where the water should not be put into use unless a fire takes place, and the water pressure in pipelines should permanently remain constant. This paper introduces the automatic regulation principle of the variable-frequency type air-pressurized water supply equipment (hereafter referred to as simply BFQS equipment) for dual purposes of daily life and fire control, which combined both technologies of speed governing by a converter and air-pressurized water supplying, then discusses some problems related to automatic control, and finally gives the experimental results of an embodiment-BPQS-100-50 water supply equipment.

• 제어로봇시스템학회:학술대회논문집
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• 1988.10a
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• pp.466-470
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• 1988

A tunable reduced-order distillation model is proposed for real-time applications. To develop the model, a binary distillation column with MaCabe-Thiele assumptions was considered first and then the governing equations for the column were reduced to a simplified vector differential equations using the collocation method combined with cubic spline interpolation function. The final reduced-order model has four tuning parameters, relative volatilities and liquid holdups for rectifying and stripping sections, respectively. To assess the applicability of the developed model,the real-time adjustment of the model was tried by recursively updating the tuning parameters using the BKF algorithm. As a result, it was found that the reduced-model follows the simulated distillation process very closely as the parameters are improved.

• 제어로봇시스템학회:학술대회논문집
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• 1988.10a
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• pp.556-561
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• 1988

Shrink-rings (Stress-rings) are used in the fabrication of dies for cold forming and powder compaction processes to increase the allowable pressures for a given die material. Optimum procedures are to minimize a die thickness under the conditions that the stress distributions in the die and stress-rings utilize fully the strength available in each of the die elements. This paper proposes a new approach, where the maximum allowable shrinking pressures are calculated on shrinkage plans in the radial direction and the fractional shrinking pressures below the maximum allowable pressures are used as the design values. Two criteria for the optimal die design are used: Maximum shear stress limit for one-piece dies and zero tensile stress limit for combined dies. A computer program, DIECOM, is developed for illustrating the computer-aided design procedures. Finally, examples for each case are presented in this paper.