• 한국산업융합학회 논문집
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• 제19권2호
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• pp.81-87
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• 2016

This paper presents a new approach to control of stable motion of single wheel driving robot system of a pitch that is controlled by an in-wheel motor and a roll that is controlled by a reaction wheel. This robot doesn'thave any actuator for a yaw axis control, which makes the derivation of the dynamics relatively simple. The Lagrange equations was applied to derive the dynamic equations of the one wheel driving robot to implement the dynamic speed control of the mobile robot. To achieve the real time speed control of the unicycle robot, the sliding mode control and optical regulator are utilized to prove the reliability while maintaining the desired speed tracking performance. In the roll controller, the sigmoid-function based robust controller has been adopted to reduce the vibration by the situation function. The optimal controller has been implemented for the pitch control to drive the unicycle robot to follow the desired velocity trajectory in real time using the state variables of pitch angle, angular velocity, angle and angular velocity of the driving wheel. The control performance of the control systems from a single dynamic model has been illustrated by the real experiments.

• 한국군사과학기술학회지
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• 제4권1호
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• pp.225-233
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• 2001

This paper deals with the transfer alignment problem of SDINS(StrapDown Inertial Navigation System) subjected to roll and pitch motions of the ship. Specifically, to reduce alignment errors induced by measurement time-delay and ship body flexure, an error compensation method is suggested based on delay state augmentation and DCM(Direction Cosine Matrix) partial matching. A linearized error model for the velocity and attitude matching transfer alignment system is first derived by linearizing the nonlinear measurement equation with respect to its time delay and augmenting the delay state into the conventional linear state equations. And then DCM partial matching is properly combined to reduce effects of a ship's Y axis flexure. The simulation results show that the suggested method is effective enough resulting in considerably less azimuth alignment errors.

• 제어로봇시스템학회논문지
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• 제19권9호
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• pp.834-838
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• 2013

This paper proposes a new ball robot which has a four axis structure and four motors that directly actuate the ball to move or to maintain the balance of the robot. For the Balancing control, it is possible to use non-model-based controller to control simply without complex formula. All the gains of the controller are heuristically adjusted during the experiments. The tilt angle is measured by IMU sensors, which is used to generate the control input of the roll and pitch controller to make the tilt angle zero. The performance of the designed control system has been verified through the real experiments with the developed ball robot.

• 제어로봇시스템학회논문지
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• 제8권2호
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• pp.178-184
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• 2002

This paper deals with the transfer alignment problem of SDINS(StrapDown Inertial Navigation System) subjected to roll and pitch motions of the ship. In order to reduce alignment errors induced by ship body flexure, a linearized error model for the velocity and attitude matching transfer alignment system is first derived by linearizing the nonlinear measurement equation with respect to the dominant y axis component and defining the flexure state of random constant type. And then a robust state estimation scheme is introduced to account for modeling uncertainty of the flexure. By interpreting the simulation results and comparing with the velocity and DCM(Direction Cosine Matrix) partial matching method, it is shown that the proposed method is effective enough to improve the azimuth alignment performance.

• 대한기계학회논문집A
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• 제36권11호
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• pp.1463-1471
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• 2012

본 논문은 3 축 영상 장치를 기존의 2 축 경계 로봇에 적용하는 설계안을 제시하고 이러한 기동형 경계 로봇의 영상 정보를 이용한 목표 추적 알고리즘을 제안하였다. 또한 가상 시뮬레이션을 이용하여 목표 추적 알고리즘을 검증하였다. 목표추적 알고리즘에서는 카메라 영상의 중심과 카메라 영상으로 포착된 목표물 중심 사이의 위치 에러를 이용하여 영상 장치의 목표 지향 벡터를 획득하고, 역기구학을 이용하여 획득한 목표 지향 벡터를 생성해 낼 수 있는 기동형 경계 로봇의 팬, 틸트 회전 요구 각도와 카메라 영상의 안정화를 위한 롤 회전 요구각도를 계산하였다. MATLAB 과 ADAMS 를 이용하여 기동형 경계 로봇의 가상 모델을 생성하고, 가상의 목표물의 움직임에 대한 가상 모델의 운동을 확인하여 영상 기반의 목표 추적 알고리즘을 검증하였다.

• 제어로봇시스템학회논문지
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• 제21권4호
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• pp.336-341
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• 2015

This paper proposes a balancing and driving control system for a Mecanum wheel ball robot which has a two axis structure and four motors. The inverted pendulum control method is adopted to maintain the balance of the ball robot while it is driving. For the balancing control, an anon-model-based controller has been designed to control the device simply without the need of a complex formula. All the gains of the controller are heuristically adjusted during the experiments. The tilt angle is measured by IMU sensors, which is used to generate the control input of the roll and pitch controller to make the tilt angle zero. For the driving control, the PID control algorithm has been adopted with angles of the wheels and the encoder data. The performance of the designed control system has been verified through the real experiments with the suggested ball robot.

• 한국자동차공학회논문집
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• 제6권1호
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• pp.163-181
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• 1998

In this study, the objective is determine the optimal design variable of engine mount system using the rubber mount of bush-type which is usually utilized in passive control to minimize vibrations of vehicle body or transmission from engine into body. The engine model adopted in this study is 4-cylinder, 4-stroke gasoline engine support- ed by 4-points. The system is modelled in 10 d.o.f.-rigid body motion of the engine & transmission in 6 d.o.f., elastic motion of vehicle body in 4 d.o.f.(1st torsional, 1st vertical and 1st & 2nd lateral bending vibration mode). To consider the elastic motion of vehicle body, find the eigenvalues and mode shapes of vehicle body by nodal testing and then determine the modal masses and stiffnesses of the body. The design variables of the engine mount system are locations, stiffness and damping coefficients of the rubber mounts(28 design variables). In case of considering the torque-roll axis for the engine, the design variables of the mount system are reduced to 22 design variables. The objective functions in optimal design process are considered by three cases, that is, 1) transmitted forces through engine mounts, 2) acceleration components of generalized coordinates for the vibration of vehicle body, 3) acceleration of specified location(where gear box) of body. three case are analyzed and compared with each other.

• 전기학회논문지
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• 제57권8호
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• pp.1362-1370
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• 2008

This paper describes the design and characteristic analysis of a novel 3-DOF(Degree of Freedom) spherical motor. For multi DOF actuating, several numbers of motors have been used. By the using of normal motors they connected each other in single joint, is necessary to a several type of complex power transmission devices. The 3-DOF spherical motor can drive roll, pitch, and yaw motion in only one unit and it is not necessary to use additional gears and links parts. Therefore the using of 3-DOF spherical motor can eliminate; combined effects of inertia, backlash, non-linear friction, and elastic deformation of gears. In this paper, we propose the novel structured 3-DOF spherical motor and derive its principles of operation. Firstly, we designed concept model of novel structured 3-DOF spherical motor. Next, we derive the control method by calculating the currents. Also, to have intuitive driving control, we express the rotor position in equivalent angle-axis system and determine the exciting period of currents from the calculation result of the currents. To verify the control method, we calculated the currents by the position of rotor. and then we analyzed the characteristics by 3D Finite Element Method when the calculated currents are excited.

• Journal of Biosystems Engineering
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• 제37권3호
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• pp.192-200
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• 2012

Purpose: Aerial application of chemicals with an agricultural helicopter allows for precise and timely spraying and reduces working labor and pollution. An attitude controller for an agricultural helicopter would be helpful to aerial application operator. The objectives of this paper are to determine the transfer function models and to estimate the handling qualities of a bare-airframe model helicopter. Methods: Transfer functions of a model unmanned helicopter were estimated by using NAVFIT and DERIVID modules of the $CIFER^{(R)}$ program to the time history data of frequency sweep flight tests. Control inputs of the transfer functions were elevator, aileron, rudder and collective pitch stick positions and the outputs were resulting on-axis movements of the fuselage. Results: Minimum realization of the transfer functions for pitch rate output to elevator control input and roll rate output to aileron control input produced second order transfer functions with undamped natural frequencies around 3.0 Hz and damping ratios of 0.139 and 0.530, respectively. The equivalent time delays of the transfer functions ranged from 0.16 to 0.44 second. Sensitivity analysis of the proposed parameters allowed derivation of minimal realization of the transfer functions. Conclusions: Handling quality of the model helicopter was addressed based on the eigenvalues of the transfer functions, corresponding undamped natural frequencies with damping ratios. The equivalent time delays of the lateral-directional motion ranged from 0.16 to 0.44 second, longer than the 0.1 to 0.15 second requirement for well-controlled typical manned aerial vehicles.

• 한국항공우주학회지
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• 제44권7호
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• pp.552-561
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• 2016

본 연구에서는 강제진동 기법을 이용하여 람다형상을 갖는 무미익 무인기의 동안정 미계수를 측정하였다. 강제진동 기법은 시험모델을 일정한 크기의 각 변위로 진동시키면서 항공기에 작용하는 공력의 시간이력(time history) 데이터를 측정하고, 입력진동 대비 공력데이터의 위상차와 진폭을 추출함으로써 비행체의 동안정 미계수를 계산하는 방법이다. 본 연구에서는 롤, 피치, 요 방향으로 각각 진동시킬 수 있는 실험 장치를 설계, 제작하여 국내 최초로 무미익 항공기의 동안정 미계수 측정 시험을 수행하였다. 롤 댐핑 동안정 미계수 측정 결과, 진동 주파수와 진동의 크기가 증가하여도 동안정 미계수의 경향성은 동일하게 나타나며, 전반적으로 측정 받음각 구간에서 안정한 특성을 보였다. 피치 댐핑 동안정 미계수의 경우 작은 진동 주파수에서 동적으로 더 안정해지며, 받음각 $15^{\circ}$ 이상에서는 동적으로 불안정해지는 경향성을 보였다. 각 시험데이터들은 반복성 시험을 통해 데이터의 신뢰성을 검증하였으며, 본 연구에 적용된 강제진동 기법이 무미익 항공기의 동안정 미계수를 성공적으로 측정할 수 있음을 확인하였다.