Attitude Control System Design Research Articles

Study on the Transverse Elastic Vibration Equation and the Generalized Aerodynamic Force of Space Vehicle

In order to avoid divergence of space vehicle attitude, structural elastic movements should be taken into consideration in the control system design. Space vehicle structure generally has a large length-diameter ratio, the corresponding rolling and longitudinal modal with higher natural frequency has a slight impact on the design of the control system, while the transverse elastic modal with lower natural frequency including pitching and yawing should be paid more attention in the design of space vehicle control system. In this paper, the influence of elastic vibration on the design of attitude control system of space vehicle is analyzed firstly. Then the transverse elastic vibration equation of spacecraft and the calculation method of generalized aerodynamic force are studied. Furthermore, the equation of elastic vibration considering the coupling effect of aerodynamic force between pitching and yawing control channels is proposed and the engineering calculation method of generalized aerodynamic force for typical stations in spacecraft is improved. The research results can provide significant reference for the design of the new generation of spacecraft control system.

Attitude determination & control system design for gravity recovery missions like GRACE

This paper is dedicated to the attitude control law synthesis for GRACE-like missions. Namely, two satellites move along the same orbit at a distance of several hundred kilometers and “look” at each other. This angular motion resembles the stabilization at unstable equilibrium position in the Orbital Frame. The reaction wheels cannot be used because they greatly affect the accelerometers measurements. Hence, only magnetorquers and thrusters may be utilized for the attitude control. Two different approaches are considered: linear quadratic regulator and Lyapunov-based controller. Control coefficients of the latter are obtained using the Floquet theory. Numerical simulation including atmospheric drag, solar radiation pressure and state vector measurements errors is carried out to validate suggested control techniques. The developed attitude determination and control system algorithms are tested for GRACE and GRACE-FO mission scenarios with relevant requirements and parameters.

High‐precision attitude determination and control system design and real‐time verification for CubeSats

SummaryThis paper presents the design and real‐time verification of a high‐precision and low‐cost attitude determination and control system (ADCS) for CubeSat based on a micro‐electro‐mechanical (MEMS) gyroscope. The CubeSat new missions require accurate and sophisticated ADCS with attitude drift adjustment. Moreover, designing an effective ADCS for the CubeSat poses a difficult challenge. The satellite comprises of a two‐unit CubeSat, which denotes that the ADCS is designed with small size, tight mass, and energy limitations. The ADCS has been enhanced in the former few years from fairly small resolution of 10 to around 0.6 m. This attitude drift, if not properly compensated, will cause a slow attitude information loss as the error in attitude rises between the actual and estimated. To correct the attitude adrift, the proposed system utilizes a MEMS gyroscope sensor which offers a comparative attitude to the Kalman filter for estimated attitude update. Real‐time verification and validation for the ADCS are performed through Matlab/Simulink environment and lab testing to prove the efficacy of the proposed system. Simulation of the ADCS shows accurate results with error of no more than 1°.

Design of attitude control system for ASRTU microsatellite

Design of attitude control system for ASRTU microsatellite

Study on the Effects of Atmospheric Parameters on Space Vehicle Design

For the space vehicle flying in the airspace and near-space, the structure safety and attitude control ability are related to the surrounding atmosphere. The distribution characteristics of atmospheric parameters, including temperature, pressure, density and wind field should be studied based on the data statistics. In this article, the spatiotemporal distribution characteristics and measurement methods of atmospheric parameters are summarized, and the effects of atmospheric parameters on the engineering design of ballistic trajectory, propulsion system, aero-thermal heating, and attitude control system are provided. These results have considerable significance in the space vehicle general design.

Modeling and Simulation of Satellite Attitude Dynamics and Control System using Modelica

The control of attitude of a satellite is difficult to verify since several subsystems of different disciplines, e.g., flexible multibody dynamics, machines, electronics and control, are involved and strongly coupled. A traditional method is to model each single discipline subsystem with a domain specific software, and combine them through interfaces. However, the problems are that lots of interfaces between software have to be developed, and manual decoupling of systems should be considered during modelling process. In this Paper, models of the dynamics and the control system are established in a unified modelling software, MWorks, which is an Integrated Development Environment of Modelica. The model can be used to verify the satellite control strategy, and also provide an effective means for satellite attitude control system design. Moreover, on this basis, the whole satellite was modelled to access state parameters changes under the coupling of the dynamic subsystem, the attitude control subsystem, the power supply subsystem, the propulsion subsystem and the integrated electronic subsystem can be synthetically considered.

Attitude Analysis of Small Satellites Using Model-Based Simulation

CubeSats, and small satellites in general, being small and relatively light, are sensitive to disturbance torques in the orbital environment. We developed a simulation tool that includes models of the major environmental torques and small satellite experiences in low Earth orbit, which allows users to study the attitude response for a given spacecraft and assist in the design of attitude control systems, such as selecting the magnet strength when using passive magnetic stabilization or designing the shape of the spacecraft when using aerodynamic attitude stabilization. The simulation tool named the Smart Nanosatellite Attitude Propagator (SNAP) has been public in precompiled form and widely used since 2010; this paper accompanies the release of SNAP’s source code with the inclusion of new models for aerodynamic torque and other new features. Details on internal models are described, including the models for orbit propagation, Earth’s magnetic field, gravity gradient torque, spacecraft shape modelling and aerodynamic torque, permanent magnetic dipole torque, and magnetic hysteresis. A discussion is presented on the significance of aerodynamic torque and magnetic hysteresis on a magnetically stabilized 3-unit CubeSat in the orbit of the International Space Station, from which many small satellites are deployed.

Design of Attitude Control System for Stratospheric Balloon Gondolas by Sliding Mode Control

This paper reports consideration of efficient design method for the azimuthal-attitude control of stratospheric balloon gondolas utilizing only a motorized pivot. To maintain sufficient robustness against variation of the model parameters, applying of sliding mode controller is tried and proposed control system is validated by numerical simulation studies.

Design of Attitude Control System for Four Rotor UAV

This paper designs the quadrotor aircraft, and the software algorithm is the core. The software structure mainly uses the quaternion to Euler angle algorithm as the core to carry out the real-time attitude calculation of the aircraft, and supplemented by the cascade PID controller algorithm to stabilize, accurately and quickly respond to the RF signal. In this paper, the final goal of stable flight is achieved by solving the flight attitude algorithm.

Cassini Spacecraft Attitude Control System Performance and Lessons Learned, 1997–2017

A sophisticated interplanetary spacecraft, Cassini–Huygens was launched on 15 October 1997. After achieving orbit at Saturn in 2004, Cassini collected science data throughout its four-year prime mission (2004–2008) and nine-year extended mission (2008–2017). The Cassini Attitude and Articulation Control Subsystem (AACS) is perhaps the spacecraft subsystem that must satisfy the most mission and science pointing requirements. The performance of the Cassini AACS design was superb from launch through end of mission. All key mission and science requirements were met with significant margins. Overviews of the Cassini attitude control system design and flight performance (in 1997–2017) are given in this paper. Processes taken by the attitude control operations team to guard against human errors are also outlined. Cassini flight experience and many lessons learned are equally applicable to the safe operations of other interplanetary missions.

Fengyun-4 Attitude Control System Design and Its In-Flight Performance

Fengyun-4, launched on 11 December 2016, is a second-generation geostationary meteorological satellite that employs a three-axis-stabilized attitude control strategy with a zero-momentum state. This Paper introduces the attitude control system of the spacecraft platform and its in-flight performance. The development status of current meteorological satellites in the same generation are reviewed. The Fengyun-4 attitude control system and technical details are presented, including highly accurate attitude determination, attitude-pointing control with high accuracy and stability requirements under the disturbance of rapid steering payloads, momentum management and adjustment, and accommodation to operate after turning 180 deg about the yaw axis, as well as fault diagnosis, isolation, and recovery. In-flight results are presented to demonstrate that the attitude control system of the spacecraft platform could fulfill the Fengyun-4 mission requirements.

Collision Avoidance and Path Following Control of Unmanned Aerial Vehicle in Hazardous Environment

Recent years have seen a rapidly increasing number of applications using unmanned aerial vehicles (UAVs). In order to greatly enhance the capabilities of UAVs working along with other manned aerial vehicles in more cluttered, hazardous, and sophisticated environments without violating the aviation traffic regulations, this paper proposes a new hybrid collision avoidance method along with a modified path following approach. The proposed hybrid collision avoidance scheme consists of a global path planner and a local collision avoidance mechanism for the purpose of greatly reducing computational efforts raised by global method, while ensuring the safe and satisfactory performance of collision avoidance. The global path planner is designed using rapidly exploring random tree (RRT), and the dynamics of UAV are also taken into consideration to generate a feasible and optimal path. The light-computational local collision avoidance mechanism, which can partially modify the globally planned path in dynamic environment when any hazardous obstacles blocking the desired path, is developed based on an intelligent fuzzy logic approach by integrating a set of decision making strategies and several aviation traffic regulations. Regarding the presented path following methodology, an improvement to the previous cross-track error calculation mechanism is made by employing the extended Kalman filter (EKF) to estimate the cross-track error. Finally, design of height and attitude control system of UAV is also addressed. Extensive simulation and experimental studies on a series of scenarios with both static and dynamic objects are conducted to demonstrate the effectiveness of the proposed hybrid collision avoidance approach and cross-track error prediction based path following method.

Torque model verification for the GOCE satellite

The modeling of torques acting on satellites is essential for the design of satellite attitude control systems. The GOCE satellite, equipped with accurate accelerometers, star trackers and GPS receivers, presents an opportunity to validate these models. Although the forces on GOCE and other accelerometer-carrying missions have been extensively analyzed in the past, a similar analysis has so far not yet been made for the torques.In this paper, we present a set of torque models for the GOCE satellite. It consists of six main parts: (1) magnetic torquer actuators, (2) aerodynamic torque, (3) gravity gradient torque, (4) solar radiation pressure torque, (5) thruster torque, and (6) passive magnetic torque. The magnetic properties of the payload are approximated using a parametrization, of which the parameters are estimated from the observation data.Based on data recorded during selected spacecraft events, the model for the control torques can be validated and error sources are identified in the other models. The models perform best in roll and pitch, where the standard deviation is reduced to 15.2% and 2.1% of the standard deviation of the control torque around those axes respectively. In yaw the standard deviation is significantly larger at 30.5%. The remaining differences between models and observations show magnetic signatures due to electric currents and signatures of aerodynamic model errors. The latter correspond well with an increase in thermosphere density and wind speed with increased geomagnetic activity. The pitch torque is found to be a potential source of vertical wind data.

AOCS design for the ATHENA X-ray telescope: challenges and solutions

The ATHENA—Advanced Telescope for High-ENergy Astrophysics—mission is currently assessed in a phase A feasibility study as L-class mission in ESA’s Cosmic Vision 2015–2025 plan, with launch foreseen in 2028. Primary mission goal is the mapping of hot gas structures and the determination of their physical properties to search for supermassive black holes. ATHENA is an X-ray telescope with a focal length of 12 m. It has a mass of ~ 7000 kg and it is ~ 15 m high with a diameter of ~ 3 m. The main mass is distributed to the mirror on the one side of the spacecraft and to the science instrument module on the other side of the spacecraft. To achieve its science goals, ATHENA performs a sky survey with precision line-of-sight pointing requirements in the order of arc seconds for absolute pointing and sub-arc seconds for relative pointing in time windows > 1 ks, all at 95% confidence level. That is very demanding for large X-ray telescopes. In addition to the precision pointing requirements, ATHENA cannot violate a certain sun exclusion zone. This is a hard constraint to prevent any stray-light falling onto the instruments, as it would immediately destroy them. The sky survey is defined by an observation plan that is demanding in terms of availability and thus spacecraft agility. The pointing and agility requirements and the fact that ATHENA is a spacecraft with high mass and volume introduce several design challenges for the attitude and orbit control system. This paper presents those challenges, corresponding solutions, and preliminary results, which have been achieved during the phase A study led by Airbus in Friedrichshafen, Germany. The main focus and contribution of this paper are the identification of research and development needs for attitude and orbit control systems to enable the ATHENA mission. In this respect, the ATHENA design challenges are discussed and addressed with the state-of-the-art design methods. This paper concludes with the main identified technology development needs and formulates specific research questions related to practical design problems. In particular, the following attitude and orbit control system design challenges are addressed: autonomous and agile large angle slew manoeuvres with exclusion zones, availability for science observations, precision line-of-sight determination as well as analysis during the design process using the ESA Pointing Error Engineering Tool and pointing control with a hexapod as line-of-sight actuator in the control loop. The last challenge, namely, the hexapod in the control loop, is without precedence in Europe and to the best knowledge of the authors in the world.

Attitude control system proposed for SERPENS-2 space mission

SERPENS mission involves research and development of nanosatellites and is inserted in a set of activities carried on by Brazilian universities in the scope of strategies coordinated by AEB (Brazilian Space agency). The first satellite of a series, SERPENS-1, was put into orbit in September 2015, retiring in March 2016. SERPENS-2 mission is currently being designed. The experiments to be carried out in SERPENS-2 are: X and Gamma rays detection; South Atlantic magnetic anomaly detection and testing of a pulsed plasma thruster. Each experiment is related to the attitude. This paper is concerned with the Attitude Determination and Control System (ADCS) design of a 3U CubeSat. A proposal of ADCS for SERPENS-II mission is described concerning both the mission and the attitude requirements. The modeling of the satellite and of its attitude dynamics is preliminarily studied considering the proposed ADCS. Results of the first control mode (de-tumbling) are presented and meet the requirements, as expected. An initial development of the second control mode is also evaluated: an attitude regulator in the local horizontal local vertical frame, with pure magnetic actuation.

Prescribed Performance Fine Attitude Control for a Flexible Hypersonic Vehicle with Unknown Initial Errors

AbstractThis is a study of a fine attitude control system design for a flexible hypersonic vehicle with unknown initial errors. A prescribed performance control method, backstepping control method, and RBF neural network method are used to design the controllers. A newly defined error transformation function is used to solve the unknown initial error issue in prescribed performance control. Different from traditional a RBF neural network, the fully‐tuned dynamic RBF neural network has better approximation ability, and the weight vector, respective centers, and width of the Gaussian function of the neural network are regulated by adaptive laws designed in the controller. The stability of the system is proved and analyzed in this paper for a fully‐tuned dynamic neural network introduced to the control system. Furthermore, prescribed performance control can guarantee the tracking errors satisfy the specified conditions and the fine attitude control can be implemented through the prescribed performance method. Finally, the simulations demonstrate the effectiveness and corrective ability of the control strategy.

The Design and Implementation of the UPMSAT-2 Attitude Control System

The paper describes in detail the design and implementation of the attitude control system of a small satellite, focusing on the hardware and software aspects. A new control algorithm has been used in order to deal with particular requirements of the system, which are related to its communication, power generation, and thermal control needs. The system is implemented on an embedded on-board computer, and the software has been developed with a model-driven approach using state-of-the-art software tools. Simulation tools have been used for software testing and validation in an integrated validation facility.

SATELLITE ATTITUDE CONTROL SYSTEM DESIGN WITH NONLINEAR DYNAMICS AND KINEMTICS OF QUATERNION USING REACTION WHEELS

The success of a space mission where the satellite must perform rapid attitude maneuvers with great angles is extremely dependent of a careful investigation of the nonlinear dynamics of the satellite. Since these big maneuvers imply in the dynamic coupling between the satellites angular motion and the actuators such as reaction wheels and/or gas jets. As a result, this coupling must be taking into account in the Attitude Control System (ACS) design. This paper presents the nonlinear model derivation of a rigid satellite and the performance comparison of two controllers designed by Lyapunov and LQR methods. The dynamics of the satellite is initially derived in the non-linear Euler equations form and the kinematics is based on the quaternion parametrization which represent the rotation and attitude motion, respectively. In the sequel, the linear model is obtained where linearization is about an operating point of the arbitrary angular velocity and the reaction wheel angular momentum. From this model, several simulations are performed in order to investigate the influence of the nonlinear dynamics in the in the SCA performance which is designed by trial and error and by the Linear Quadratic Regulator approaches. The ACS performance is evaluated considering the capacity of the reaction wheels to maintain the stability and to control the angular velocity and the attitude of the satellite. The stability is investigated comparing the location of the poles and zeros of the open and closed loops. The ACS performance is evaluated comparing the amount of energy spend by each control law. Keywords: Satellite Control, nonlinear dynamics, LQR and Lyapunov theory

Mechanical means for controlling the geometry of optical spacecraft attitude control systems and the necessary accuracy of these means

The accuracy of modern spacecraft attitude sensors has recently come to exceed the accuracy provided by the rigidity of the mechanical designs of spacecraft. One possible solution to this problem is to introduce additional sensors measuring the mutual orientation of the attitude sensors into the design of attitude control systems. In this paper we consider the questions of whether the simplest and most reliable mechanical distance measurement sensors can be used and whether their accuracy is sufficient for this purpose.

A fully tuned RACS for flight control system

This paper presents the design of a roll attitude control system (RACS) based on bacterial foraging particle swarm optimised (BFPSO) proportional integral and derivative (PID) autopilot that controls the roll angle of an aircraft. To achieve the high degree of spiral stability desired in aircraft flight control system (AFCS) requires the use of RACS. The RACS uses feedback mechanism to maintain the roll attitude in presence of disturbances and responds rapidly to the commands from the pilot. Here a new algorithm is proposed which combines the advantages of both PSO and BFO to form a new algorithm called BFPSO. The parameters such as Kp, Ki and Kd of PID-based RACS controller are tuned by BFPSO algorithm to achieve the dynamic stability as required by the pilot while spinning an aircraft. Finally, it is found from simulation, proposed controller gives the best performance compared to PSOPID, BFOPID and RBFNC controller.