• Journal of Advanced Navigation Technology
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• v.16 no.4
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• pp.571-577
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• 2012

In this paper, we design a flight controller using a dynamic compensator for a small unmanned aerial vehicle. The proposed method ensures flight stability during altitude holding and waypoints passing by improving the transient response and steady state error. The control system consists of dual feedback loops with an inner loop and a outer loop. The inner loop has a PD controller to improves the transient response and the outer loop has a dynamic compensator to reduce overshoot in the transient response and improve the steady state error. The performance of the proposed method is evaluated by flight test on a small UAV.

• Proceedings of the KIEE Conference
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• 2000.11d
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• pp.686-688
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• 2000

In this paper, a new method for system identification is proposed. Unknown dynamic system is identified to the second order transfer function, which can be applied to PID controller design. First, overshoot$(o_s)$, settling time$(t_s)$, and steady state value$(y_{ss})$ are obtained from the step response of unknown dynamic system. And then, we can get the second order transfer function using equations which are extracted from those three parameters$(o_s,t_s,y_{ss})$ through mathmatical analysis. In addition, simulation is carried out to show excellent performance of proposed identification method compare with other.

• Proceedings of the KIEE Conference
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• 1988.11a
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• pp.53-55
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• 1988

The application of Sliding Mode Control for inproving the dynamic response of a Multi-Phase-Bipolar (MPB) Brushless DC motor based position Brushless DC motor system is presented. Sliding Mode Control gives fast dynamic response with no overshoot and zero steady state error. It has the important feature of bins highly robust. A design procedure is outlined for the Sliding Mode Controller for a MPB Brushless DC motor. Digital computer simulation of the overall position control system is carried out using a time domain model in the d-q reference frame.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2003.10a
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• pp.257-260
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• 2003

Dynamic simulation program for a smart UAV turbojet engine was developed. The transient simulation program utilized the CMP(Constant Mass flow) method and Euler integration method for integration of excess torque. The transient performance analysis was carried out by increasing from the idle to the maximum rotational speed of the gas generator. To observe engine dynamic behavior, fuel flow was monitored through a step and a ramp increase. When the fuel was increased as a step function the overshoot of the turbine inlet temperature exceeded the limit temperature.

• 제어로봇시스템학회:학술대회논문집
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• 1990.10b
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• pp.907-912
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• 1990

An approach to robot force control, which allows force manipulations to be realized without overshot and overdamping while in the presence of unknown environment, is given in this paper. The main idea is to use dynamic compensation for known robot parts and fuzzy compensation for unknown environment so as to improve system performance. The fuzzy compensation is implemented by using rule based fuzzy approach to identify unknown environment. The establishment of proposed control system consists of following two stages. First, similar to the resolved acceleration control method, dynamic compensation and PID control based on known robot dynamics, kinematics and estimated environment compliance is introduced. To avoid overshoot the whole control system is constructed overdamped. In the second stage, the unknown environment stiffness is estimated by using fuzzy reasoning, where the fuzzy estimation rules are obtained priori as the expression of the relationship between environment stiffness and system response. Based on simulation result, comparisons between cases with or without fuzzy identifications are given, which illustrate the improvement achieved.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.11a
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• pp.558-562
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• 2000

This research is concerned with the experiments on buckling characteristics of strain energy hinge(SEH) for solar arrays. The dynamic characteristics of the strain energy hinge is very important since it affects the shape and speed of the solar array deployment. The rapid deployment results in overshoot and undesirable residual vibrations. In this study, we carry out a series of buckling experiments to identify the dynamic characteristics of the SEH, which is made of strip measures. Buckling tests were done on the single-plate, double-plate and triple-plate SEH and VSEH. The experimental results show that the SEH has a very complex buckling behavior which can not be coped with theoretically. The modeling problem of the SEH is also discussed.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.45-46
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• 2006

In this paper, a dual stage servo mechanism has been developed for image tracking system to improve transient control performances such as small rise time, small overshoot, small settling time, etc. A secondary stage, a platform, actuated by a pair of electro-magnets is mounted on a conventional elevation gimbal. In this mechanism, the gimbal provides large range but slow motion and the platform provides small range but fast positioning. A sliding mode control is applied to the platform positioning to attain robust performances and stability in the presence of the disturbance related to dynamic coupling of the gimbal and the platform. Results from experiments illustrate that the suggested dual stage mechanism controlled by the sliding mode control is effective in improving transient responses and attenuating the disturbance related with dynamic coupling.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.03a
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• pp.499-505
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• 2004

A Propulsion System of the CRW(Canard Rotor Wing) type UAV(Unmanned Aerial Vehicle) was composed of the turbojet engine to generate the propulsive exhaust gas, and the duct system including straight bent ducts, tip-jet nozzles, a master valve and a variable main nozzle for three flight modes such as lift/landing mode, low speed transition flight mode and high speed forward flight mode. In this study, in order to operate safely the propulsion system, the dynamic Performance behavior of the system was modeled and simulated using the SIMULIN $K^{ }$, which is the user-friendly GUI type dynamic analysis tool provided by MATLA $B^{ }$. In the transient performance model, the inter-component volume model was used. The performance analysis using the developed models was performed at various flight condition, valve angle positions and fuel flow schedules, and these results could set the safe flight mode transition region to satisfy the inlet temperature overshoot limitation as well as the compressor surge margin. Performance analysis results using the SIMULIN $K^{ }$ performance program were compared with them using the commercial program GSP.m GSP.

• Journal of Power Electronics
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• v.15 no.1
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• pp.160-176
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• 2015

This paper presents a method of designing optimal integer- and fractional-order proportional-integral-derivative (FOPID) controllers for a boost converter to gain a set of favorable characteristics at various operating points. A Pareto-based multi-objective optimization approach called strength Pareto evolutionary algorithm (SPEA) is used to obtain fast and low overshoot start-up and dynamic responses and switching stability. The optimization approach generates a set of optimal gains called Pareto set, which corresponds to a Pareto front. The Pareto front is a set of optimal results for objective functions. These results provide designers with a trade-off look-up table, in which they can easily choose any of the optimal gains based on design requirements. The SPEA also overcomes the difficulties of tuning the FOPID controller, which is an extension to the classic integer-order PID controllers and potentially promises better results. The proposed optimized FOPID controller provides an excellent start-up response and the desired dynamic response. This paper presents a detailed comparison of the optimum integer- and the fractional-order PID controllers. Extensive simulation and experimental results prove the superiority of the proposed design methodology to achieve a wide set of desired technical goals.

• Journal of Aerospace System Engineering
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• v.15 no.1
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• pp.47-55
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• 2021

When an abnormal landing occurs, aircraft structures should be designed to guarantee occupants survivability without preventing egress. To find out fire root causes at crash, lots of fixed aircraft crash tests were conducted. Appropriate crash load factors were established with the comprehension of structural behavior based on dynamic analysis and investigation of human tolerance. Cargo restraint criteria were set up considering passengers safety and operational cost while analyzing past cargo aircraft accident data using a probabilistic approach. Reviewing results of past crash tests, current crash landing load factor was appreciated physically, medically, and economically.