• Aerospace Engineering and Technology
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• v.1 no.1
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• pp.65-71
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• 2002

KOMPSAT-1 AOCS mode divided into three major mode like Sun, Maneuver, Science Mode. The Maneuver mode consist of attitude hold and Δ-V Burn submode. This paper focus on the analysis of AOCS Maneuver Mode characteristics based on on-orbit playback data. The nadir pointing performance of attitude hold submode and the process for Δ-V Burn firing with plus/ minus 90 degree pitch/ roll maneuvering was verified. And also verified that the on-orbit performance meets the AOCS subsystem specification as designed.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1392-1395
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• 2004

In order to successfully develop attitude and orbit control subsystem(AOCS), AOCS engineer performs hardware selection, controller design and analysis, control logic and interface verification on electrical test bed, integrated system test, polarity test, and finally verification on orbit after launching. Attitude and orbit control subsystem for KOMPSAT-2 consists of standby mode, sun mode, maneuver mode, science mode, and power safe mode to stabilize and to control the spacecraft for performing the mission. The sun mode is usually divided into sun point submode, earth search submode and safe hold submode. The maneuver mode is divided into attitude hold submode and ${\triangle}$ V submode, while the science mode divided into science coarse submode and science fine submode. Moreover, it is added to back-up mode which uses wheels as an actuator for sun mode and maneuver mode. In this paper, we describe the controller design process and the performance of the design results with respect to the sun mode and the maneuver mode based on thrusters as an actuator using on flexible model.

• Journal of Institute of Control, Robotics and Systems
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• v.5 no.3
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• pp.370-378
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• 1999

KOMPSAT is a three-axis stabilized light weight satellite, and one of the main mission objectives of the KOMPSAT is to conduct scientific and technological analysis in the areas of high resolution imaging and ocean color imaging. This kind of mission requires the satellite to roll up to 45 degrees. Bang-bang control for this rolling maneuver may activate the flexible modes, and therefore cause satellite pointing performance degradation. To deal with this problem, the roll attitude control system, especially for the science mode and maneuver mode of the KOMPSAT, is first verified by numerical simulation. And the open-loop control law for roll maneuver is proposed by use of series expansion and optimization. The proposed control law is applied to KOMPSAT to see its effectiveness.

• Journal of Astronomy and Space Sciences
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• v.15 no.1
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• pp.235-244
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• 1998

The solutions of orbital maneuver problem using the sliding mode control in the presence of the erath gravitational perturbations is obtained. Especially, the optimization of consuming fuel for maneuver is performed. The impulsive solution to Lambert's problem using the combined equation method to minimize total ${\Delta}V is used for the desired orbit and the maneuver times. Two-step sliding mode control method is introduced for satisfying the boundary conditions of finite-thrust rendezvous problem at the end of maneuver time. Using the new approach to the orbit maneuver problem, two-step sliding mode control, orbit maneuvers are processed. The solutions to a rendezvous using the optimal control are obtained, and they are compared to the results by two-step sliding control.According to the new approach for orbit maneuver, the thrust-coast-thrust type controller is obtained to make satellite to track desired Lambert's orbit, and the total ${\Delta}V$ required for maneuver is resonable in comparison with the impulsive solution to Lambert's problem. The final state variables, also are close to the boundary conditions at the end of maneuver times.

• Journal of Auto-vehicle Safety Association
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• v.5 no.1
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• pp.16-24
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• 2013

Some GM (General Motors) vehicles are using a GMLAN (General Motors Local Area Network) communication protocol for control and diagnostics. The airbag control module uses vehicle speed information from the GMLAN to record the vehicle speed as pre-crash information. In order to use the vehicle speed information for crash reconstruction purposes, it helps to be able to understand the accuracy of the data. The actual vehicle speed is not expected to be the same as the GMLAN indicated speed in some situations like a spin or if there is hard braking. This paper compares the actual vehicle speed and vehicle speed information during specific vehicle maneuvers. Actual vehicle speed is calculated from a GPS sensor, while GMLAN vehicle speed is calculated from transmission output sensor by the Engine control module (ECM). Vehicle maneuvers defined as Mode #1, Mode #2, Mode #3. The Mode #1 maneuver simulates wheel lock-up and skidding f by hard-braking at a specific speed. The Mode #2 maneuver simulates a 90degree turn using a J-turn maneuver at a specific speed. The Mode#3 maneuver simulates a 180 degree turn using a spin type of maneuver at a specific speed. The study then compares the GMLAN speed and GPS speed to see what speed difference exists between them. The results of this paper are applicable to GM vehicles only. This paper catalogs the performance and limitations of two vehicles as useful reference for crash reconstructions where there is a need to understand the speed indicated in the pre-crash section of the SDM data.

• Journal of Mechanical Science and Technology
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• v.15 no.2
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• pp.143-151
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• 2001

In the paper, a robust control mechanism is presented to maneuver a flexible spacecraft with the deflection reduction during large slewing operation at the same time. For deflection reduction and maneuvering of the flexible spacecraft, a control mechanism is developed with the application of stochastic optimal sliding-mode control, a linear tracking model and input shaping technique. A start-coast-stop maneuver is employed as a slewing strategy. It is shown that the control mechanism with he strategic maneuver results in better performance and is more efficient than rigid-body-like maneuver, by applying to the Spacecraft Control Laboratory Experiment (SCOLE) system in a space environment.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.3
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• pp.224-232
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• 2015

In order to develop an active safety system which avoids or mitigates collisions with preceding vehicles such as autonomous emergency braking (AEB), accurate state estimation of the nearby vehicles is very important. In this paper, an algorithm is proposed using 3 dynamic models to better estimate the state of a vehicle which has various dynamic patterns in both longitudinal and lateral direction. In particular, the proposed algorithm is based on the Interacting Multiple Model (IMM) method which employs three different dynamic models, in cruise mode, lateral maneuver mode and longitudinal maneuver mode. In addition, a Probabilistic Data Association Filter (PDAF) is utilized as a data association algorithm which can improve the reliability of the measurement under a clutter environment. In order to verify the performance of the proposed method, it is simulated in comparison with a Kalman filter method which employs a single dynamic model. Finally, the proposed method is validated using radar data obtained from the field test in the proving ground.

• International Journal of Aeronautical and Space Sciences
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• v.13 no.3
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• pp.369-376
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• 2012

A nonlinear robust guidance law is designed for missiles against a maneuvering target by incorporating sliding-mode and optimal control theories based on the state dependent Riccati equation (SDRE) to achieve robustness against target accelerations. The guidance law is derived based on three-dimensional nonlinear engagement kinematics and its robustness against disturbances is proved by the second method of Lyapunov. A new switching surface is considered in the sliding-mode control design. The proposed guidance law requires the maximum value of the target maneuver, and therefore opposed to the conventional augmented proportional navigation guidance (APNG) law, complete information about the target maneuver is not necessary, and hence it is simple to implement in practical applications. Considering different types of target maneuvers, several scenario simulations are performed. Simulation results confirm that the proposed guidance law has much better robustness, faster convergence, and smaller final time and control effort in comparison to the sliding-mode guidance (SMG) and APNG laws.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.1125-1130
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• 2007

This paper presents a maneuver analysis of a full-vehicle featuring electrorheological (ER) suspension and ER brake. In order to achieve this goal, an ER damper and an ER valve pressure modulator are devised to construct ER suspension and ER brake systems, respectively. After formulating the governing equations of the ER damper and ER valve pressure modulator, they are designed and manufactured for a middle-sized passenger vehicle, and their field-dependent characteristics are experimentally evaluated. The governing equation of motion for the full-vehicle is then established and integrated with the governing equations of the ER suspension and ER brake. Subsequently, a sky-hook controller for the ER suspension and a sliding mode controller for the ER brake are formulated and implemented. Control performances such as vertical displacement and braking distance of vehicle are evaluated under various driving conditions through computer simulations.

• International Journal of Aeronautical and Space Sciences
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• v.14 no.1
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• pp.58-66
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• 2013

This paper addresses the performance of three different types of attitude control systems for the Quad-rotor UAV to perform the flip maneuver. For this purpose, Quad-rotor UAV's 6-DOF dynamic model is derived, and it was used for designing an attitude controller of the Quad-rotor UAV. Attitude controllers are designed by three different methods. One is the open-loop control system design, another is the PD control system design, and the last method is the sliding mode control system design. Performances of all controllers are tested by 6-DOF simulation. In case of the open-loop control system, control inputs are calculated by the quad-rotor dynamic model and thrust system model that are identified by the thrust test. The 6-DOF realtime simulation environment was constructed in order to verify the performances of attitude controllers.