• 전자공학회논문지 IE
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• v.45 no.4
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• pp.11-18
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• 2008

This study is implementation of attitude control system(ACS - Attitude Control System). for a multi legs robot. This study designs H/W of Inertial Measurement Unit (IMU) and attitude control algorithm S/W. Compare performance with Mtx and MTx in order to verify action performance of this system after implementation, and will verify a system integrated IMU of a multi-legs robot. ACS uses Gyro and an accelerometer and an earth magnetism sensor, and it is a system controlling a roll, pitch angle attitude of an object. Generally, low price MEMS is difficult to calculate a correct situation of an object as an error occurs severely the Inertial sensor. This study implements IMU in order to develop ACS as use MEMS, accelerometer, Gyro sensor and earth magnetism sensor. Design algorithm each a roll, pitch, yaw attitude guaranteeing regular performance, and do poling in a system as include an attitude calculation program in an IMU system implemented. Mixed output of Gyro and an accelerometer, and recompensed a roll, pitch angle, and loaded in this study on a target platform in order to implement the ACS which guaranteed performance more than a continuously regular level, and operated by real time, and did porting, and verified.

• Journal of the Korean Society of Propulsion Engineers
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• v.19 no.3
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• pp.54-64
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• 2015

This paper deals with an acceleration controller design for a kill vehicle equipped with a divert and attitude control system (DACS). In the proposed method, the attitude control system (ACS) is used to produce the thrust command to nullify angle-of-attack. For the angle-of-attack control, a nonlinear angle-of-attack controller is proposed based on the feedback linearization methodology. Since the flight path angle is identical to the attitude angle under the condition of zero angle-of-attack, the divert control system (DCS) can directly produce the lateral acceleration which is demanded from the guidance loop. In the proposed method, we can minimize the aerodynamic uncertainty due to the propulsive force. Additionally, we can simplify the operation logic of DCS and ACS. In this paper, nonlinear simulations are performed to show the performance of the proposed method.

• Journal of the Korean Society of Propulsion Engineers
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• v.14 no.6
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• pp.103-120
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• 2010

A development history of the thrusters used for space-vehicle orbit maneuver/attitude control is reviewed with their performance characteristics. Especially, a scrutiny is made for the current and practical application of TVC/Gimbal/Thrusters to the roll/pitch/yaw-axis control of each stage of launch vehicles. It is well perceived that a precise 3-axis attitude control system (ACS) must be equipped on the final stage of space launch vehicles (SLV) for an attainment of orbit-insertion accuracy. Under the superior reliability as well as moderate performance features, the monopropellant hydrazine thrusters occupy most of the SLV's 3-axis ACS currently operated. Domestic development status of the medium-thrust-level thruster is shortly introduced, finally.

• Journal of Mechanical Science and Technology
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• v.17 no.12
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• pp.1912-1921
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• 2003

This paper presents a global mode modeling of space structures and a control scheme from the practical point of view. Since the size of the satellite has become bigger and the accuracy of attitude control more strictly required, it is necessary to consider the structural flexibility of the spacecraft. Although it is well known that the finite element (FE) model can accurately model the flexibility of the satellite, there are associated problems : FE model has the system matrix with high order and does not provide any physical insights, and is available only after all structural features have been decided. Therefore, it is almost impossible to design attitude and orbit controller using FE model unless the structural features are in place. In order to deal with this problem, the control design scheme with the global mode (GM) model is suggested. This paper describes a flexible structure modeling and three-axis controller design process and demonstrates the adequate performance of the design with respect to the maneuverability by applying it to a large flexible spacecraft model.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.352-355
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• 2005

This paper describes an engineering model development of a pulsed plasma thruster, which is capable of an impulse bit of 20uNs and a specific impulse of 800s. The solid fuel which is Teflon allows for a self-contained, inert and stable propellant system. And, the PPT technology makes it possible to consider a revolutionary attitude control system (ACS) concept providing stabilization and pointing accuracies previously obtainable only with reaction wheels, with reduced mass and power requirements.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.30-30
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• 2000

In the three axis control of satellite by using reaction wheel and gyro, a Gyro carries out measuring of the attitude angie and the attitude angular velocity. The Gyro is operated by the electronic part and the mechanic actuator. The digital part of the electronic part is consisted of the FPGA (Field Programmable Gate Array), which is one of the methods for designing VLSI (Very Large Scale Integrated Circuit), and the mechanic actuator processes the input/output data by the dynamic model. In the research of the mixed mode of Gyro, the simulation is accomplished by SABER of the mixed mode simulator and the results for the practical implementation of the satellite ACS (Attitude Control System) interfaced with the data processing are proposed.

• Journal of Institute of Control, Robotics and Systems
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• v.8 no.1
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• pp.54-59
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• 2002

In the three-axis control of satellites by using on-board actuators, gyros are usually used to measure the attitude angles and angular rates. The gyros are operated by electronic parts and mechanical actuators. The digital components of the electronic parts consist of largely FPGA (Field Programmable Gate Array) as one of the methods for VLSI(Very Large Scale Integrated) circuit design, while the mechanical parts provide output signal directly by mechanical actuation of a spinning rotor. In this research, a mixed mode of gyro is implemented in FGA. In addition to the hardware implementation, the simulation study was conducted by using the SABER for the mixed mode simulator. Results for the practical implementation of the satellite ACS (Attitude Control System) interfaced with the data processing are also presented to validate the FPGA implementation.

• Journal of the Korean Society of Propulsion Engineers
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• v.17 no.1
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• pp.1-8
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• 2013

A liquid-monopropellant hydrazine thruster has several outstanding advantages such as relatively-simple structure, long/stable propellant storability, clean exhaust products, and so on. Therefore hydrazine thruster has such a wide application as orbit and attitude control system (ACS) for space vehicles. A hydrazine thruster with the medium-level thrust to be used in the ACS of space launch vehicles (SLV) has been developed, and its ground firing test result is presented in terms of thrust, impulse bit, temperature, and chamber pressure. It is verified through the performance test that the response and repeatability of thrust are very excellent, and the thrust efficiencies compared to its ideal requirement are larger than 93%.

• Journal of the Korean Society of Propulsion Engineers
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• v.21 no.5
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• pp.61-70
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• 2017

Robust thrust distribution method of solid DACS is researched. For the case of the system which has higher number of actuation nozzles than the degree of freedom of thrust to be controlled, the robust thrust allocation law which accommodate the abnormal operation is suggested. Assuming the situation that some nozzles are uncontrollable, the error between nozzle throat area command and response can be calculated. The error is used for realtime reshaping of weighting matrix. From the weighting effect, the nozzle which operated abnormally has low responsibility for the command then, the thrust error is reduced. The suggested algorithm is verified by the simulation of abnormal operation condition of DCS and ACS nozzle respectively.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.2
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• pp.144-152
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• 2011

This paper presents a new scheme for fault detection and isolation in the satellite system. The purpose of this paper is to develop a fault detection, isolation and diagnosis algorithm based on the bank of interacting multiple model (IMM) filter for both total and partial faults in a satellite attitude control system (ACS). In this paper, IMM are utilized for detection and diagnosis of anticipated actuator faults in a satellite ACS. Other fault detection, isolation (FDI) schemes using conventional IMM are compared with the proposed FDI scheme. The FDI procedure is developed in two stages. In the first stage, 11 EKFs actuator fault models are designed to detect wherever actuator faults occur. In the second stage of the FDI scheme, two filters are designed to identify the fault type which is either the total or partial fault. An important feature of the proposed FDI scheme can decrease fault isolation time and figure out not only fault detection and isolation but also fault type identification.