• 제어로봇시스템학회:학술대회논문집
• /
• 2002.10a
• /
• pp.120.4-120
• /
• 2002

$\textbullet$ In order to operate EP actuator, high voltage is applied to that. $\textbullet$ Our previous control algorithm for an EP actuator was PI method with constant gain. $\textbullet$ But this Control method is limitation such as rising time, steady-state error, and settling time. $\textbullet$ A neural network algorithm is proposed for improvement of performance. $\textbullet$ To do this, neural network algorithm changes the gain of PI control. $\textbullet$ In order to efficient drive EP actuator, the gain is changed at some point. $\textbullet$ Neural network method improve the performance of operation.

• Journal of Mechanical Science and Technology
• /
• v.16 no.2
• /
• pp.155-164
• /
• 2002

The power steering system for vehicles is becoming essential for supporting the steering efforts of the drivers, especially for the parking lot maneuver Although hydraulic power steering has been widely used for years, its efficiency is not high enough. The problems associated with a hydraulic howe. steering system can be solved by a motor driven power steering (MDPS) system. In this study, a dynamic model and a control algorithm for the ball screw type of MDPS system have been derived and analyzed by using the method of discrete modeling technology. To improve steering feel and power steering characteristics, two derivative gains are added to the conventional power boosting control algorithm. Through simulations, the effects of the control gain on the steering angle gain were verified in the frequency domain. The steering returnability and steering torque phase lag in on-center handling test were also evaluated in the time domain.

• Journal of Power System Engineering
• /
• v.18 no.5
• /
• pp.28-34
• /
• 2014

This paper deals with optimum PI controller design using genetic algorithm to improve control performance and robustness for an oil cooler system. The optimum PI gain was found to minimize an object function, integrated absolute error, and to satisfy control design specifications such as overshoot and settling time based on practical transfer function of the oil cooler system. The control performance and robustness were investigated by comparing indicial responses and Bode diagram analysis with respect to three kinds of PI gains obtained from different gain decision manners. Moreover, the robustness against to input disturbances, sinusoidal wave form and abrupt single pulse, was evaluated. The computer simulation results showed that the suggested optimum gain can establish desirable control performance and strong robustness with easy design process.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.8 no.1
• /
• pp.124-134
• /
• 2000

The power wteering system for automobiles is becoming core popular for supporting steering efforts of the drivers, especially for a parking lot maneuver. Though hydraulic power steering has been widely used for a long time, the efficiency of that is not high enough. The motor driven power steering system can solve the problems associated with the hydraulic power steering system. In this study, dynamic model and control algorithm of the ball screw type of MDPS systenem have been derived and analysed by using the method of discrete modeling technology. To improve steering feel and power steering characteristics, the additional scheme is proposed to the conventional power boosting control algorithm. Through simulations, control gain effects to the steering angle gain in the frequency domain were verified. The steering returnability and steering torque phase lag in on-center handing test were performed also.

• Journal of the Korean Society of Industry Convergence
• /
• v.18 no.1
• /
• pp.1-9
• /
• 2015

This research dealt with a two-degree-of-freedom controller which was used for 2-dimensional force generator based on an linear motor. The gain margin of the controller may be reduced when the time constant is near to the sampling time of a discrete controller. In case of low gain controller, it cannot satisfy the control performance. A two-degree-of-freedom controller based on PI-control was proposed. It can manage performance and stability respectively. It also had a kind of a feed-forward control. This scheme can not only lessen gain of conventional PI controller in order to stability but also obtain high tracking performance.

• Proceedings of the Korean Society of Marine Engineers Conference
• /
• 2001.05a
• /
• pp.207-212
• /
• 2001

In this paper, a method to be able to decide the possible maximum gain of P, PI control for the retarded processes under stable condition is proposed. At first, adjustable parameter set causing stability limit are obtained based on the frequency domain condition which makes the roots of transfer function locate on the $j\omega$ axis. And the cut-in frequency $\omega{_p}$ to bring the parameter set to P control from PI control is derived by an equation with 2 parameters L and $T_m$ given, then $\omega{_p}$ is used to compute the maximum gain with stable condition. For the calculation, the controlled process of first order system with time delay element is introduced and all parameters are presumed to be time invariant.

• Aerospace Engineering and Technology
• /
• v.7 no.1
• /
• pp.61-67
• /
• 2008

To design flight control law of an unmanned aerial vehicle, automated control gain determination program was developed. The procedure for determination of control gain was formulated as the control gains were designed from the optimal solutions of the optimization problem. PSO algorithm, which is one of the evolutionary computation method, and SQP algorithm, which is one of the nonlinear programming method, are used as optimization problem solver. Thru this technique, computation time required for finding the optimal solution is decreased to 1/5 of that of PSO algorithm and more accurate optimal solution is obtained.

• Journal of the Semiconductor & Display Technology
• /
• v.16 no.3
• /
• pp.25-30
• /
• 2017

Arago's disk system consists of a speed controller of the DC motor (inner loop controller) and a position controller of the magnetic bar angle (main controller), which are implemented by the design of the PI and PID controller, respectively. First, we analyzed the nonlinear characteristics of the Arago disk system and found the operating point range of three locations as a result. In this paper, a gain scheduler method was applied to guarantee a constant control performance in the range of $0{\sim}130^{\circ}C$, and a structure to change the controller according to the control reference value based on the previously obtained operating points was experimentally implemented. The Distributed Control Systems (DCS) configuration using the Controller Area Network (CAN) was used to verify the proposed method by improving the operational efficiency of the entire experimental system. So, simplicity of the circuit and easy diagnosis were achieved through a single CAN bus communication.

• Journal of Institute of Control, Robotics and Systems
• /
• v.8 no.5
• /
• pp.363-372
• /
• 2002

In ship operation, the roll motions can seriously degrade the performance of mechanical and personnel effectiveness. So many studies for the roll stabilization system design have been performed and good results have been achieved. In many studies, the stabilizing fins are used. Recently rudders, which have been extensively modified, have been used exclusively to stabilize the roll. But, in the roll stabilization control system, the control performance is very sensitive to the ship speed. So, we can see that it is important to consider the ship speed in the rudder roll control system design. The gain-scheduling control technique is very useful in the control problem incorporating time varying parameters which can be measured in real time. Based on this fact, in this paper we examine the;$H_{\infty}$-Gain Scheduling control design technique. Therefore, we assume that a parameter, the ship speed which can be estimated in real time, is varying and apply the gain-scheduling control technique to design the course keeping and anti-rolling control system far a ship. In this control system, the controller dynamics is adjusted in real-time according to time-varying plant parameters. The simulation result shows that the proposed control strategy is shown to be useful for cases when the ship speed is varying and robust to disturbances like wind and wave.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1997.04a
• /
• pp.288-292
• /
• 1997

Positioning accuracy largely depends on the variation of friction force in guide table, geometric accuracy of feed unit like as ballscrew and controllable accrecy of servo unit, in general. This paper deals with improvement of microstep resolution about hydrostatic table. Torque control mode have a advantage in microstep test, and more stable than velocity control mode in low velocity motion. Hydro static table have the elastic behavior within several .mu.m, so different character exist between the elastic motion and rolling motion. Integral gain is dominant than other gain in elastic motion. In order to improve response time in elastic motion,increasing gain is suggested within the stable region.