Space science/space station attached payload pointing accommodation study: Technology assessment white paper

Technology assessment is performed for pointing systems that accommodate payloads of large mass and large dimensions. Related technology areas are also examined. These related areas include active thermal lines or power cables across gimbals, new materials for increased passive damping, tethered pointing, and inertially reacting pointing systems. Conclusions, issues and concerns, and recommendations regarding the status and development of large pointing systems for space applications are made based on the performed assessments

A Uniform Method of Mechanical Disturbance Torque Measurement and Reduction for the Seeker Gimbal in the Assembly Process

In the manufacturing process of seekers, the reduction of disturbance torques (DTs) is a critical but time-consuming work. The innovation of the paper is to present a uniform method to measure and reduce mechanical DTs during gimbal’s assembly process. Firstly, the relationships between assembly parameters and DTs are established and analyzed by theoretical model. And then, a measuring system is established to measure the driven torque of the gimbal’s torque motor. With the goal of stabilizing and minimizing the driven torque, all assembly parameters relating to DTs could be adjusted. Through the proof of a lot of experiments, this proposed method could reduce the bias and fluctuation of these mechanical DTs. This method could also be used for the mechanical DTs reduction of most similar productions and improve the quality and efficiency during their system assembly process

Systems Development of a Two-Axis Stabilised Platform to Facilitate Astronomical Observations

Inertially Stabilised Platforms (ISPs) aim to control the line-of-sight between a sensor and a target. They perform two distinct operations; keeping track of the target as the sensor host and the target move in inertial space and attenuating rotational disturbances incurred to the sensor by host vehicle motion. This project aimed to develop a two-axis ISP for use in astronomical applications. It represents the initial development of all systems of a low-cost ISP designed for a 3.5” compound telescope. To achieve this, relevant literature describing the various components of an ISP were reviewed to inform the design, implementation and testing cycle which comprised most of the project. A set of system specifications was developed to guide design decisions. The performance of the implemented system was compared against these specifications once the project was complete. During the project, the electro-mechanical structure of the ISP was designed and implemented, including a mechanical assembly designed to mount a camera and inertially and geometrically model the specified telescope. This allowed the ISP to be tested at a lower cost than with the telescope itself. The associated electrical systems were specified and configured. An image processing script capable of detecting and locating the centre of the Moon in the camera field of view was written in Python and implemented on a Raspberry Pi Computer. A complete simulation model for the system was written in the simulation language, Simul_C_EM, and used to design various controllers for the ISP control system and help verify certain estimated system parameters such as gimbal friction. For each gimbal, PI controllers were designed to allow manual orientation control of the telescope, compensated P controllers were designed to achieve target tracking, and compensated PI controllers were designed to reject rotational disturbances. These were implemented in C on an STM32F0 microcontroller tasked with managing the various control and communications tasks required by the system. Finally, a user interface was written in LabVIEW to facilitate intuitive user control of the system and perform datalogging of the system runtime data. Testing of the system showed good correlation between the hardware and the simulated results indicating an accurate simulation model that can be used to test future design developments

Error modeling of precision orientation sensors in a fixed base simulation

Models of noise and dynamic characteristics of gyro and autocollimator for very small signal levels are presented. Measurements were evaluated using spectral techniques for identifying noise from base motion. The experiment was constructed to measure the precession, due to relativistic effects, of an extremely precise earth-orbiting gyroscope. The design goal for nonrelativistic gyro drift is 0.001 arcsec per year. An analogous fixed base simulator was used in developing methods of instrument error modeling and performance evaluation applicable to the relativity experiment sensors and other precision pointing instruments. Analysis of autocollimator spectra uncovered the presence of a platform gimbal resonance. The source of resonance was isolated to gimbal bearing elastic restraint properties most apparent at very small levels of motion. A model of these properties which include both elastic and coulomb friction characteristics is discussed, and a describing function developed

Design of strapdown gyroscopes for a dynamic environment Interim scientific report

Error analysis for single degree of freedom integrating gyro, and figure of merit relating gyro errors to orientation error of strapdown inertial reference syste

Mercury/Gemini program design survey. NASA/ERC design criteria program stability, guidance and control

Mercury/Gemini stability, guidance, and control equipment design criteri

Apollo guidance, navigation and control - Design survey of the Apollo inertial subsystem

Design, development, and testing of inertial guidance and navigation systems for Apollo projec

A systems engineering approach to disturbance minimization for spacecraft utilizing controlled structures technology

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1991.Includes bibliographical references (leaves 159-163).by Christopher Emil Eyerman.M.S

Report on the development of the Manned Orbital Research Laboratory /MORL/ system utilization potential. Task area IV - MORL SYSTEM improvement study, book 3

Manned Orbital Research Laboratory system improvement study on stabilization and control subsystem