• Journal of the Korean Society of Manufacturing Process Engineers
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• v.16 no.5
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• pp.91-98
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• 2017

This study was conducted to optimize the spring constant and the damping coefficient, which are design parameters of the tractor cabin suspension system, to minimize the ride vibration. A 3D tractor MBD (multi-body dynamics) model with a cabin suspension system was developed using a dynamic analysis program (Recurdyn). Using the developed model and optimization algorithm, the spring constant and the damping coefficient, which are the design parameters of the cabin suspension for the tractor, was were optimized so thatto minimize the maximum overshoot for the vertical displacement of the cabin was minimized. The percent maximum overshoot of the tractor cabin was simulated for the 13 initial models, which were obtained using the ISCD-II method, and for the 3 additional SAO models presented in the optimization algorithm software. The model that represents with the smallest percent maximum overshoot among the 16 models was selected as the optimized model. The percent maximum overshoot of the optimized model was about approximately 5% lower than that of the existing model.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1995.10b
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• pp.139-144
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• 1995

LIBL(Linguistic Instruction Based Leaning) is an effective learning algorithm for fuzzy controller which interpretes and uses natural language of human The possibiliy of the LIBL algorithm to the fuzzy control of dynamic systems is investigated in this paper. Rise time, percent overshoot, and steady stste are proposed as suitable meaning elements for dynamic systems. A supervisor is able to give "higer-level linguistic instruction" to the learning algorithm through these three meaning elements Simulation results for a DC servo motor show the validity of the proposed algorithm.

• Journal of Biosystems Engineering
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• v.14 no.1
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• pp.1-7
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• 1989

This study was carried out to develop a system and methodology to simulate the engine load variation occuring during agricultural field operations for a laboratory engine test. The system consisted of an electric dynamometer, an Apple II microcomputer, and a data acquisition and control system. Several pieces of instruments were utilized to measure various engine performance data. Both engine torque and engine speed were fully controlled by a computer program. The dynamic characteristics of the system were analyzed through a series of tests and the limitations on the load simulation test were presented. The results of the study are summarized as follows: 1. Engine speed and toque were controlled by a computer program. The use of a stepping motor and reduction gears enabled engine speed be controlled within 1 rpm. 2. The natural frequency of the dynamometer-engine system was found to be around 5 Hz, at which the load simulation would be impossible because of resonance. 3. For the harmonic inputs with the frequencies above the natural frequency, the signal attenuated too much and therefore the load simulation was impossible. 4. The step response of the system showed an overshoot of 24.5 percent and the settling time for 5 percent criterion was around 3 seconds. 5. When actual field test data are utilized for load simulation, a low-pass filter should be included to attenuate the frequency components around and above the natural frequency.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.2
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• pp.705-709
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• 2005

In this paper, we introduce fuzzy algorithm similar to human's way of thinking and designed collision detection system of vehicles. First, before the model vehicles design, we did simulation collision detection using PID and Fuzzy Controller. As a result, P.O that is Percent Overshoot when make use of PID controller happened from smallest 32% to 45%. But, In case of using fuzzy controller they produced about 10% in 7% in case use 25 rule. We designed model vehicles that introduce Auto Guided Vehicle(AGV) with confirmed result in simulation. We set Polaroid 6500 sensor on the front of model automobile because distinguish existence automobile to the head. And we composed motor drive part to run vehicles and 80C196KC processor for control movement of vehicles influenced on distance data of the front vehicles that receive from supersonic waves sensor. In case of using Fuzzy controller, last value percent error happened about maximum 15% in smallest 5%, and we confirmed that distance with front vehicles kept when state hold time is about maximum 16 seconds in smallest 10 seconds.

• Journal of Sensor Science and Technology
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• v.24 no.6
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• pp.412-418
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• 2015

In this paper, a new method for obtaining PID coefficients which are essential to a temperature stabilization process has been proposed. This method starts from measuring the open loop transfer function of the module, then the closed loop transfer function embodying PID control can be produced based on this. Finally, the simulations using a few PID coefficients and the performance analysis for those results provide the best PID coefficients which are effective in a fast setting to a target temperature, a less current needed, and less deviation from steady state. The measurement using the derived PID coefficients, $K_p=1.6$,$K_i=0.8$,$K_d=0.3$ showed $T_s=7.4[sec]$, %OS = 16, and stabilization within ${\pm}0.02[^{\circ}C]$ for several hours. In addition to light sources like SOA, the proposed method can be utilized for any device needs temperature stabilization.