Dynamic modelling and control of a gimballed airborne antenna platform with mass unbalance and friction

Download
2018
Şeref, Tuğçe
Inertial stabilized gimballed systems are widely-used in many applications to achieve a high precision positioning. Airborne antennas pointing target as a part of the satellite communication may be examples of such systems. This thesis presents the dynamic modelling and control of a two axes gimballed airborne antenna platform. First, reference frames and the transformation matrices are defined to build up the motion of the antenna and kinematic equations of each gimbal are derived. Next, the dynamic equations including mass unbalance of the gimbals and the friction torques about pivot points are obtained. Then, the study puts emphasis on the concepts of the static and dynamic mass unbalance and also argues how much each mass unbalance affects the operation. Furthermore, a dynamic model, Lugre friction, establishes the friction torques for both of the gimbals. All these studies results in the complete dynamic model of the two axes gimballed airborne antenna platform. The overall system model is implemented inMATLAB/Simulink environment. Next, system identification studies to determine the parameters of the Lugre friction model have been performed by two different methods based on real and simulated data. Finally, PI based controllers have been designed for the overall system in several design stages.

Suggestions

Cogging Torque Disturbance Rejection for a Low-cost Gimbal Motor and a Controller Design with Practical Considerations
Ozdogan, Gokhan; Leblebicioğlu, Mehmet Kemal (2019-01-01)
In many robotic applications and inertially stabilized electro-optic gimbal systems, precise positioning and speed control are highly important concepts. Due to size and weight limitations, motor is required to be small but torque density is desired to be high. In high torque and cheap PMSM and BLDC motors, cogging torque and friction are usually the challenging disturbance sources. In this study, cogging torque and friction are identified using position sensors which already exist in gimbal systems, so the...
Design and analysis of radar antenna structure with optimum dynamic behavior
Sun, Enver; Özgen, Gökhan Osman; Yaman, Yavuz; Department of Mechanical Engineering (2016)
With the advance of technology the radar antenna structures are being smaller and their design alternatives are quite numerous that they can be produced in different shapes and can be conformed to original structures such as body panel of an aircraft or car which are composed of light weight thin shell structures. Radar antennas as an integral part of the air or ground vehicles are subjected to various dynamic loadings which effects its overall radiation pattern which results overall degradation of antenna ...
Design and analysis of antennas mounted on cylinders for avionics applications
Özcan, Mustafa; Aydın Çivi, Hatice Özlem; Department of Electrical and Electronics Engineering (2015)
Conformal antenna structures are widely used in airframes because of not disturbing the aerodynamic characteristics. In this study, stripline fed conformal slot antennas of rectangular and rounded bow-tie shaped geometries, and coplanar patch antennas are designed to comply with the design requirements of a telemetry application in the frequency band of 2225-2275 MHz. Furthermore, parametric studies are carried out for some crucial design parameters in order to understand the relation between the antenna ph...
Method of moments analysis of slotted waveguide antenna arrays
Altuntaş, Abdülkerim; Alatan, Lale; Department of Electrical and Electronics Engineering (2014)
Slotted waveguide antenna arrays are used extensively in many applications because of their high power handling capability, planarity, low loss and reduced profile. After the synthesis of such an array, the design should be verified by analyzing the array with an efficient simulation tool which is accurate, fast and flexible. Although FEM (Finite Element Method) based commercial softwares are very accurate and flexible, they are not sufficiently fast especially when it comes to optimization and fine tuning....
ISAR imaging and motion compensation
Küçükkılıç, Talip; Dural Ünver, Mevlüde Gülbin; Department of Electrical and Electronics Engineering (2006)
In Inverse Synthetic Aperture Radar (ISAR) systems the motion of the target can be classified in two main categories: Translational Motion and Rotational Motion. A small degree of rotational motion is required in order to generate the synthetic aperture of the ISAR systems. On the other hand, the remaining part of the target’s motion, that is any degree of translational motion and the large degree of rotational motion, degrades ISAR image quality. Motion compensation techniques focus on eliminating the effe...
Citation Formats
T. Şeref, “Dynamic modelling and control of a gimballed airborne antenna platform with mass unbalance and friction,” M.S. - Master of Science, Middle East Technical University, 2018.