MIMO H ∞ control of three-axis ship-mounted mobile antenna systems (original) (raw)

Modelling and stabilization of a three-axis ship-mounted mobile antenna system

A mobile satellite communication antenna is a device installed on a moving carrier for mobile satellite communication. Gimballed motorized pedestals are used to eliminate the effect of disturbance and maintain uninterrupted communication when the carrier is moving. Mobile satellite communication antennas are becoming increasingly more popular due many advantages of mobile satellite communication. In this paper, a three-axis ship-mounted antenna on a pedestal gim-bal system is studied. We study the problem with a different perspective and method from the previous work for two-axis antenna pedestals. The former studies treat the subsystems to be isolated and design controllers separately, which neglect the coupling effects in the dynamics of two or three-axis antenna pedestal gimbals. We treat three subsystems as a whole and derive the dynamic model of the system using the Newton–Euler method. Based on the dynamic model, linear PI controllers are designed to stabilize the antenna to keep its orientation towards the satellite. The design objective of the control system is to direct the on-board antenna toward a satellite and to keep its orientation unaltered despite the effect of sea waves disturbing the antenna. Simulation results are presented to show the stabilization performance of the system with the synthesized controllers.

Design and Implementation of Attitude Stabilization System for Marine Satellite Tracking Antenna

Electronics

Marine Satellite Tracking Antenna (MSTA) is an important shipboard device for ships to bidirectionally communicate with the outside. The attitude stabilization system is an important part of MSTA for keeping the antenna dish tracking the geostationary satellite in the presence of severe ship dynamics. In this paper, the designed high-performance attitude stabilization system is introduced, including hardware system, model identification and controller design. The detailed procedure for identifying the stepper motor model is stated, which is different from conventional procedure. The design procedure of the robust controller based on H ∞ loop shaping is given. The designed attitude stabilization system was tested on a Stewart platform that was used as the ship simulator. From the testing results, it can be seen that the performance of designed attitude stabilization system is very high and the tracking angle error can be limited to within ± 0.15 deg, which satisfies the performance r...

Antenna Azimuth Position Control System using PID Controller & State-Feedback Controller Approach

International Journal of Electrical and Computer Engineering (IJECE), 2018

This paper analyzed two controllers with the view to improve the overall control of an antenna azimuth position. Frequency ranges were utilized for the PID controller in the system; while Ziegler-Nichols was used to tune the PID parameter gains. A state feedback controller was formulated from the state-space equation and pole-placements were adopted to ensure the model design complied with the specifications to meet transient response. MATLAB Simulink platform was used for the system simulation. The system response for both the two controllers were analyzed and compared to ascertain the best controller with best azimuth positioning for the antenna. It was observed that state-feedback controller provided the best azimuth positioning control with a little settling time, some value of overshoot and no steady-state error is detected. 1. INTRODUCTION The issue of antenna azimuth position control has become one of the many aspects that have drawn the attention of researchers in the control of antenna placement [1]. These interests are due to the major roles and enhance performances that would be derived from correct azimuth positioning of an antenna. Several techniques were proposed to achieve an optimum control of the azimuth position but such positioning remains a control challenging problem. Hoi et al [2] conducted a research on satellite tracking using fuzzy proportional integral derivative PID control techniques and the conventional PID controller to get the best in performance on satellite tracking. Both the step response in the two techniques presented evidence of chattering phenomena which may lead to poor and weak result and conclusion respectively. Xuan et al [3] introduced a discrete control system using PID controller to achieve a better control on satellite antenna angle deviation. The shortcoming of this work is lack of proper tuning of the PID gains for precise results. Soltana et al [4] considered the case of overseas satellite telecommunication where the control system was applied to an on-board motorized antenna; the separate controller was designed to detect a fault in the satellite control. Though the controller was not robust enough to enable handle the detected fault in the controlled signal. The research of [5] and that of [6] is basically using PID and Linear Quadratic Gaussian (LQG) for the antenna azimuth position control system; both researchers were faced with similar shortcomings of degraded performance due to system nonlinearities and delay in reaching setpoint. A much better settling time and less overshoot were achieved by [7] where the Fuzzy logic controller (FLC) and a self-tuning fuzzy logic controller (STFLC) was utilized in the design but chattering phenomena were reported as the setback. All these make the antenna

Modeling, Design and Control of a Ship Carried 3 DOF Stabilized Platform

The system for stabilizing platform of a ship carried antenna a nd its core component are discussed in this study. Relevant mathematics model of these components are established. Thus, the dynamic model of the system is deduced including the effects of friction, inertia and torque motors. Using Solid Works, we built the mechanical structure, including the servo machine of each part of the system. The system under consideration is a system with strong interactions between three channels. By using the concept of decentralized control, a control structure is developed that is composed of three control loops, each of which is associated with a single-variable controller. First, PID controller was applied; then, Takagi-Sugeno (TS) fuzzy controller was used for controlling the platform. Simulation tests were established using Simulink of Matlab. The obtained results have demonstrated the feasibility and effectiveness of the proposed fuzzy approach comparing to the PID controller. Simulati...

Antenna Position Control System, Simulation and Real-Time Study

2016

Antenna pointing angle is the core of the quality of the transmitted/received signal. Since most of the antennas work in an outdoor environment, their pointing angles might be subjected to different types of disturbances- specifically wind gust- that might deviate them from their correct positions. The process of the position re-correction might be difficult especially if this is done manually due to the precision needed, and sometimes the location of the antenna, as well as its size, are another challenging issues that make the manual correction more difficult. This work is a study and design of a control system that can carry the antenna to the required position as well as fix it on that position by resisting the disturbances. The resistance and the removal of the effect of disturbances require a closed loop control system and application of control algorithm (The one that is used here is Proportional-Integral-Derivative (PID) controller). The total work is a simulation and real-t...

Positioning Control of Satellite Antenna for High Speed Response Performance

IPTEK, The Journal of Engineering, 2024

Dish antennas are essential elements in establishing communication between satellite and earth station. The response speed of the position control process of a dish antenna mounted on a moving vehicle that communicates via NigComSat-1R with a central control office is affected by round trip or time delay. Therefore, there is need to design a control system that will address this problem in order to achieve high speed positioning response. The mathematical models representing the dynamics of the antenna positioning system were obtained. A back propagation neural network (BPNN) based proportional integral and derivative (PID) controller was designed and added to the antenna position control loop. The resulting system was modelled in MATLAB. Simulation results indicated that it provided a rise time of 0.027 s, settling time of 1.06 s and overshoot of 0% at peak time of 0.06 s. This shows that the response speed of the control process using the designed BPNN-PID is 37 degree per second. Comparison with previous controllers applied to the same system indicated that BPNN-PID controller outperformed all of them. Generally, the BPNN-PID controller is suitable for high speed position control of the antenna and improves overall performance.

Servomotor-based Antenna Positioning Control System Design using Hybrid PID-LQR Controller

2016

There are increasing needs to develop control systems that can be used to automatically point Direct Current (DC) servomotor driven parabolic antennas to moving targets, notably in satellite tracking, to maintain the desired line of sight for quality communication. Although many researchers nowadays focus on artificial intelligence techniques, it is reckoned here that a well designed optimal linear controller can still give acceptable results at reduced system cost and complexity. In this paper the design and control of DC servomotor-based antenna positioning system has been addressed and simulated in MATLAB/SIMULINK software. The aim is to minimize deviations from the desired position. The response of the system is analyzed and results are first obtained by using well tuned Proportional-Integral-Derivative (PID) controller. The results of the PID controller are further improved by adding Linear Quadratic Regulator (LQR) which apart from optimizing the system response increases the ...

Control system for satellite tracking antenna

IFAC Conference on Cost Effective Automation in Networked Product Development and Manufacturing, 2007

This paper describes a control system developed for a satellite tracking antenna located at National Institute for Space Research (Natal-Brazil). Both driving system (hardware) and the control software are shown. The system has used materials (cables, antenna, motors, inverters,etc) from a deactivated satellite ground station. The software was developed using the GNU/Linux platform and the Comedi Package, used for developing the AD/DA board drivers and for providing libraries to the main program.

The Improvement of System Architecture for Robustness Control of Hexapod Antenna Tracking

2018 15th International Conference on Electrical Engineering/Electronics, Computer, Telecommunications and Information Technology (ECTI-CON)

This paper presents the antenna tracking based on hexapod system under the R&D project which is called WATERs (Wise Antenna of Transmission Execution & Receiving system). This system will be used to transmit telecommand (TC) and receive telemetry (TM) for full operation of THAICHOTE and future satellite. Due to the large size of the antenna and very high frequency are used that, the tracking system should be emphasized the accuracy for supporting a narrow beamwidth. Moreover, control architecture should be appropriately designed for satellite operation as well, which it needs high reliability. Originally, the installation has been performed as a testing lab, such that the capability cannot support the operation. Then, the improvement is needed by improving the synchronous control for hexapod system and the appropriate Graphic User Interface (GUI). This system was installed under the Siemens product including drive Simotion, SCOUT and WinCC software. Apart from the architecture and GUI software, the mathematical model is also one part which must be transformed to inverse and forward kinematic model. The new mathematical model is generally used, and it is advantage for realizing actual position of the antenna. The detail of improvement of the system will be described in this paper.