• Journal of Biosystems Engineering
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• v.43 no.4
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• pp.379-385
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• 2018

Purpose: Postharvest handling of onions (harvesting, cleaning, grading, cooling, storing, and transport) should be performed continually to reduce costs and improve quality. The purpose of this study is to a) determine the design parameters and operating conditions of anion auto-dumping that constitutes a key component of the postharvest bulk handling machinery system, and b) to perform a performance test with the auto-dump prototype system. Methods: Kinematic analyses and computer simulations of the auto-dump mechanism were applied to analyze the operating conditions and design parameters. Results: The optimum working condition for the auto-dump was determined from kinetic analyses. In addition, the interaction between the velocity of the hydraulic cylinder and the angular velocity of the auto-dump were analyzed in order to control the bulk handling machinery system. The acting forces and optimum operating conditions of the hydraulic cylinder were determined by analyzing the forces related to the mass of inertia of the auto-dump assembly during rotation. The method of controlling the feeding rate of onions in terms of the uniformity of the stacking pattern and the control of the entire system was better than the two-stage method of controlling the rotational speed of the auto-dump. Based on the performance test with the prototype for the auto-dump, the stacking pattern and rigidity of the system were analyzed. Conclusions: These results would be of great importance in the postharvest bulk handling machinery system for onions.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.2 no.2
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• pp.231-239
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• 1998

In this paper, we designed a current controlling servo system for speed control of a PMSM. In existing auto-tuning methods for PI controller parameters, the output response is delayed and the overshoot is generated. By solving these existing problems in this paper, a new PI auto-tuning method is applied to the speed controller for fast-response and reduced overshoot. PMSM servo systems offer a great advantage in unmanned factories where a great number of servo motors are employed, because of its easy maintenance characteristics and controllability. The implemented servo system is composed of absolute position detecting circuits of a rotor, a new auto-tuning PI control algorithm, a speed controller by using DSP, and power driving section. The proposed servo system is verified for it's practical availability by considering experimental results.

• Journal of the Korea Convergence Society
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• v.4 no.2
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• pp.43-50
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• 2013

Sliding mode control(SMC) are carried out in this literature. And to make the controllers perform better, fuzzy logic was chosen,it makes PID controller auto-tuning parameters and reduced the chattering problem of sliding mode control. Since SMC take error and derivative of error as inputs, after comparison some results are obtained.PID controller response faster yet sliding mode control is much steadier. However certain problems cannot be ignored that the chattering phenomenal cannot be reduced entirely and this motion may hurt the machine; this project only considered a simple system, there is no guarantee PID can work as well as in this case for a much more complex system. MATLAB simulink was the main approach to obtain the performance of the two controllers: to observe the control output of the two controllers, electric circuit and special controllers are designed and tested in MATLAB.

• 제어로봇시스템학회:학술대회논문집
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• 1987.10a
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• pp.724-728
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• 1987

Recently, two degrees of freedom PID control systems have attracted attention, because of their better process control quality for both set point variable tracking and disturbance resistivity than that of conventional PID control systems. This paper describes a new auto-tuning method for the two degrees of freedom PID control system based on a newly developed model matching method in the frequency domain. This new method has been introduced into a two degrees of freedom PID auto-tuning controller, named AdTune TOSDIC-21D8. The superior features of the controller and the results of field tests Are presented.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1624-1627
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• 2005

We proposed a design technique for auto-landing guidance and control system. This technique utilizes linear controller and neural network. Main features of this technique is to use conventional linear controller and compensate for the error coming from the model uncertainties and/or reference model mismatch. In this study, the multi-perceptron neural network with single hidden layer is adopted to compensate for the errors. Glide-slope capture logic for auto-landing guidance and control system is designed in this technique. From the simulation results, it is observed that the responses of velocity and pitch angle to commands are fairly good, which are directly related to control inputs of throttle and elevator, respectively.

• Proceedings of the KIEE Conference
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• 2007.04a
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• pp.319-321
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• 2007

This paper introduces a general overview of the 6000m class deep-sea ROV. Hemire and Henuvy. and then describes its motion control system. It is developed by Korea Ocean Research & Development Institute(KORDI) for 6 years since 2001. sponsored by the Ministry of Maritime Affairs and, Fisheries (MOMAF). Hemire is remotely operated by a fiber optic telemetry. where 6 thrusters are controlled by operator in manual mode and by auto depth control and auto heading control in auto mode. In this paper. operational mechanism of manual and automatic mode with some convenient functions for operator is desc.ribed. Finally, results of sea trial conducted at the Philippine sea where a depth is 5.770m are shown.

• The Transactions of the Korean Institute of Power Electronics
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• v.5 no.6
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• pp.552-559
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• 2000

Most of the sensorless vector control methods use the equivalent circuit of induction motors. Therefore parameter auto-measurement of drive motor is essential function in commercial sensorless vector control inverters. The accuracy of motor parameter measurement greatly affects the performance of sensorless vector control. In this paper limitations of conventional measurement methods are examined, and new measurement methods are proposed to solve those limitations.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.109-109
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• 2000

In process industries, more than 90% of the control loops have PID controller. Futhermore, the most control systems are using classical PID controllers for their process control. Various auto-tuning methods of PID gains using relay-feedback are presented recently. In order to get the desired control performance, the correct tuning of PID controller is very important. This paper suggests how to tune of digital PID gains using information for both the Nyquist critical point by conventional method and another point by the relay feedback and hidden time-delay term. Simulation results show that the proposed controller has better performance than the conventional method.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.2
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• pp.257-264
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• 2007

In order to obtain a fine picture, a camera has many convenient functions. Its representative functions are Auto Focus(AF), Auto White Balance(AWB) and Auto Exposure(AE). In this paper, we present the new algorithm of Auto Exposure control system, one of its useful functions The proposed algorithm of Auto Exposure control system is based on IIR Filter with Variable Time Constant. First, in order to establish the standards of exposure control, we compare change of the picture luminance with luminance of an object in the Zone system. Second, we make an ideal characteristic graph of luminance by using the results. Finally, we can find the value of the right exposure by comparing an ideal characteristic graph of the luminance with the value of the current expose of a scene. We can find an appropriate exposure as comparing the ideal characteristic graph of the luminance with current exposure of a scene. In order to find a suitable exposure state, we make use of IIR Filter instead of a conventional method using micro-controller. In this paper, the proposed system has therefore simple structure, we use it for compact image sensor module used in the handheld device.

• 제어로봇시스템학회:학술대회논문집
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• 1989.10a
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• pp.643-648
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• 1989

This paper presents a theoretic study and computer simulation of models and approaches for dynamical obstacle avoidance by mobile robots. The movement of obstacles in unknown environment is described by any one or a combination of three models. The control strategy of the mobile robots is formulated based on one of three approaches. A trajectory-guided control strategy for dynamical obstacle avoidance has been developed. The method greatly simplifies the control process of mobile robots, and is computationally attractive.