• Journal of the Korea Institute of Military Science and Technology
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• v.8 no.3 s.22
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• pp.92-100
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• 2005

The objective of this paper is to design a sliding mode controller of an electro-mechanical fin actuation system using extended reducer-observer(ERO) which is used in order to estimate the velocity. The employed observer enables proper estimation of the plant state variables, even in the case of the constant or slow varying load torque disturbances. The effectiveness of this control scheme is verified by comparison with a PID control through a series of simulation studies. The simulation results show that the sliding mode control designed with the ERO gives good control performances.

• Journal of the Korea Institute of Military Science and Technology
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• v.10 no.3
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• pp.181-188
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• 2007

This paper presents a torque control method of a hydraulic actuation system for measuring the dynamic stiffness of missile fin actuators. We propose a new control technique called Dual Dynamic Torque Feedback Control(DDTFC), which improves the stability of the torque control system and enables fast tracking of torque command. The developed control scheme is derived from the physical understanding based on mathematical modelling and analysis. The dynamics of hydraulic torque control servo-system is unravelled via physics-based modelling and nonparametric system identification. In order to verify the effectiveness of the method, the experiment is carried out with a test equipment for measuring the dynamic stiffness. The experiment and simulation results show that DDTFC gives stability improvement.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.1
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• pp.70-75
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• 2010

The objective of this paper is to propose a new velocity measurement method for an electro-mechanical fin actuator. The model of the electro-mechanical fin actuator includes uncertainties such as unknown disturbances and parameter variations in flight condition. So, an electro-mechanical fin actuator system needs robust control algorithm which requires not only position information but also velocity information. Usually, analog tachometers have been used for velocity feedback in an electro-mechanical fin actuator. However, using these types of sensors have problems such as the cost, space, and malfunction. These problems lead to propose a new velocity measurement method using linear type Hall-effect sensor. In order to verify the proposed method, several experiments are performed using Model Following Sliding Mode Controller(MFSMC). It is shown that the MFSMC with a new velocity measurement method using linear type Hall-effect sensor can satisfy the requirements without using of velocity sensor.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10a
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• pp.1104-1109
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• 1991

Recently, Pneumatic Actuation System (PAS) has been used increasingly as a high performance fin-control servo actuation systems because of the special advantages of pneumatic units: primarily their low cost, small size, light weight, and tolerance to broad temperature extremes. In this study, a nonlinear model of PAS is derived through the detailed analysis of the major components in the typical system. The model includes nonlinear flow-pressure relationships of the flow through the solenoid valve openings and orifices, PWM algorithm for driving two solenoid valves as a closed-center 3-way valve for minimum gas consumption, solenoid valve dynamics, saturation, and friction. Simulation results are compared with the experimental ones for square and sinusoidal inputs to see the validity of the model. Independent of the shape and magnitude of the input signals, both results are in good agreements with minor difference.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.537-541
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• 2003

In order to control the missiles by aerodynamics, control surfaces sometime called fins are used. Deflection angles of these fins are the right control variables of the aerodynamics, but aerodynamicists prefer to use analytic variables called aileron, elevator and rudder instead of these physical variables, because these three analytic variables dominantly influence on the roll, pitch and yaw channels of the missile maneuver, respectively, and each can be assumed a linear combination of four fin deflection angles. On that basis, roll, pitch and yaw autopilots for controlling the attitudes or lateral acceleration of the missile are designed, and as a consequence outputs of each autopilot are aileron, elevator and rudder commands, respectively. In the existing fin control scheme for the typical tail-fin controlled cruciform missiles, firstly these outputs are distributed to four fin defection commands, and after that four fins are actuated by fin controllers so that their deflections follow the commands. This paper shows that performance of such control schemes can be degraded significantly when fin actuators have certain physical constraints such as slew rate, voltage or current limit, uncertainty of actuator dynamics, and so on, and propose a new control scheme which alleviates such problems. This scheme can be widely applied to various fin actuation systems. But in this paper, for convenience, tail-fin controlled cruciform missile is taken as an example, and it is shown that a proposed control scheme gives better performance than the existing one.

• Aerospace Engineering and Technology
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• v.1 no.1
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• pp.141-146
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• 2002

During dynamic flight by propulsion of rocket engine, in the atmosphere, the attitude control of flight vehicle can be accomplished by the aerodynamic fin actuator. But, in the outer space, the method of TVC(Thrust Vector Control) is only depend on for it. There are many systems which were developed for TVC. In our research, among them we adopted gimbal engine actuation system which could control the vector of thrust by swivelling rocket engine connected by gimbal. There are electro-hydraulic, electro-mechanical and pneumatic system which can be used as gimbal engine actuation system, but the electro-hydraulic system that has high ratio of output power to mass is preferred for the high power system. In this note, we made a mathematical model of the electro-hydraulic gimbal engine actuation system for the TVC of KSR-III in detail and on the base of this model we performed a simulation study. And then, we verified the model by making a comparison between the simulation and the experiments on the real system.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.11
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• pp.1300-1305
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• 2009

The various electromagnetic based actuation(EMA) methods have been proposed for actuating microrobot. The advantage of EMA is that it can provide wireless driving to microrobot. In this reason a lot of researchers have been focusing on the EMA driven microrobot. This paper proposed a swimming microrobot driven by external alternating magnet field which is generated by two pairs of Helmholtz coils. The microrobot has a fish-like shape and consists of a buoyant robot body, a permanent magnet, and a fin. The fin is directly linked to the permanent magnet and the magnet is swung by the alternating magnet field, which makes the propulsion and steering power of the robot. In this paper, firstly, we designed the locomotive mechanism of the microrobot boy EMA. Secondly, we set up the control system. Finally, we demonstrated the swimming robot and evaluated the performance of the microrobot by the experiments.

• Journal of the Korea Institute of Military Science and Technology
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• v.22 no.3
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• pp.392-400
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• 2019

This paper provides a fin actuation system of missile based on electromagnetic-spring mechanism to miniaturize the system and lower the cost. Compared with proportional electro-mechanical actuators, the output of Electromagnetic-Spring Actuators(EMSA) has two or three discrete states, but the mechanical configuration of EMSA is simple since it does not need power trains like gears. The simple mechanism of EMSA makes it easy to build small size, low cost, and relatively high torque actuators. However, fast response time is required to improve the dynamic performance and accuracy of missiles since bang-off-bang operation of EMSA affects the flight performance of missile. In this paper the development of EMSA including parameter optimization and mathematical modeling is described. The simulation results using Simulink and experimental test results of prototype EMSAs are presented.

• Composites Research
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• v.27 no.2
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• pp.47-51
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• 2014

The purpose of the present study is to develop lightweight and simple smart actuators in order to replace conventional hydraulic/pneumatic actuators, and to apply the developed actuators to the actuation systems of a small unmanned air vehicle. This research describes the procedures of design, manufacturing of the piezo-composite actuator, and the performance evaluation. From the test results of the developed devices, we found the possibility of piezo-composite actuator could be used as a control surface of a small UAV system. We have designed and manufactured two kinds of piezo-composite actuators, unimorph actuator and bimorph actuator. The manufactured actuators were evaluated through the performance testes. It was found that the bimorph type actuator showed more linear angle change for the same excitation voltage variation than unimorph type. It is expected that piezo-composite actuator has a possibility to be used not only as a control surface of small unmanned flying vehicle but also as a control surface actuator of a guided missile fin through the miniaturization of power supply and control system.