Skylab's Astronaut Maneuvering Unit (Experiment M509) — A Comparison of Six Degree of Freedom Simulation and on-Orbit Flight

1974 ◽  
Vol 18 (2) ◽  
pp. 187-187
Author(s):  
A. M. Ray
Keyword(s):  
Space Shuttle ◽  
Space Station ◽  
Degree Of Freedom ◽  
Test Bed ◽  
Control Logic ◽  
Test And Evaluation ◽  
Unit Design ◽  
Design Requirements ◽  
Experiment Hardware ◽  
Six Degree Of Freedom

A test bed type astronaut maneuvering unit was designed and evaluated with the assistance of Martin Marietta's six degree of freedom simulator. Four different control modes were developed for this unit for test and evaluation inside Skylab's 22 foot diameter orbital workshop. The orbital tests have provided the experience and technology base necessary for space Shuttle and space station astronaut maneuvering unit design requirements. This paper is an overview of the M509 experiment hardware, procedures, and results with emphasis on the comparison between on-orbit test results and the six degree of freedom simulator. The simulator was used to develop the unit's design requirements, evaluate the control logic parameters, and for developing maneuvers and training the crew. The simulator will also be flown by the Skylab crews in May for post flight evaluation and simulator calibration. (Films of the simulations and on-orbit flight are available as part of this presentation.)

Design Requirements for Autonomous Multivehicle Surface-Underwater Operations

2009 ◽  
Vol 43 (2) ◽  
pp. 61-72 ◽  
Author(s):  
Brian S. Bingham ◽  
Eric F. Prechtl ◽  
Richard A. Wilson
Keyword(s):  
Autonomous Vehicles ◽  
Data Transfer ◽  
Vertical Displacement ◽  
Degree Of Freedom ◽  
Unmanned Underwater Vehicles ◽  
Sea Trial ◽  
Performance Specification ◽  
Model Based ◽  
Design Requirements ◽  
Six Degree Of Freedom

AbstractFuture autonomous marine missions will depend on the seamless coordination of autonomous vehicles: unmanned surface vehicles (USVs), unmanned underwater vehicles (UUVs) and unmanned aerial vehicles (UAVs). Such coordination will enable important inter-vehicle applications such as autonomous refueling, high-throughput data transfer and periodic maintenance to extend the mission length. A critical enabling capability is the autonomous capture, retrieval and deployment of a UUV from a USV platform. As a first step toward solving this problem, we propose a performance specification that quantifies the necessary motion compensation required to safely and reliably operate a USV and UUV in concert in the dynamic marine environment. To accomplish this, we use a model-based approach to predict the motion of typical vehicles under the influence of the same sea conditions. We summarize the predictions succinctly using a scalar performance metric, the peak-to-peak vertical displacement, as a function of vehicle type, sea-state and vehicle formation.To substantiate this model-based approach experimentally, we present sea-trial data and compare the empirical observations to model predictions. The results show that although simple three degree-of-freedom models do not capture the full complexity of an actual six degree-of-freedom ship motion, they can prove expedient in an engineering context for quantifying the design requirements of a USV-UUV capture, deployment and retrieval system.

Iterative feedback control based on frequency response model for a six-degree-of-freedom micro-vibration platform

2021 ◽  
pp. 107754632199731
Author(s):  
He Zhu ◽  
Shuai He ◽  
Zhenbang Xu ◽  
XiaoMing Wang ◽  
Chao Qin ◽  
...  
Keyword(s):  
Feedback Control ◽  
Frequency Response ◽  
Control Strategy ◽  
Degree Of Freedom ◽  
Small Displacement ◽  
Response Model ◽  
Parameter Uncertainties ◽  
Micro Vibration ◽  
Six Degree Of Freedom ◽  
Iterative Feedback

In this article, a six-degree-of-freedom (6-DOF) micro-vibration platform (6-MVP) based on the Gough–Stewart configuration is designed to reproduce the 6-DOF micro-vibration that occurs at the installation surfaces of sensitive space-based instruments such as large space optical loads and laser communications equipment. The platform’s dynamic model is simplified because of the small displacement characteristics of micro-vibrations. By considering the multifrequency line spectrum characteristics of micro-vibrations and the parameter uncertainties, an iterative feedback control strategy based on a frequency response model is designed, and the effectiveness of the proposed control strategy is verified by performing integrated simulations. Finally, micro-vibration experiments are performed with a 10 kg load on the platform. The results of these micro-vibration experiments show that after several iterations, the amplitude control errors are less than 3% and the phase control errors are less than 1°. The control strategy presented in this article offers the advantages of a simple algorithm and high precision and it can also be used to control other similar micro-vibration platforms.

scholarly journals Design and Calibration of a Hall Effect System for Measurement of Six-Degree-of-Freedom Motion within a Stacked Column

Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3740
Author(s):  
Olafur Oddbjornsson ◽  
Panos Kloukinas ◽  
Tansu Gokce ◽  
Kate Bourne ◽  
Tony Horseman ◽  
...  
Keyword(s):  
Hall Effect ◽  
Degrees Of Freedom ◽  
Reactor Core ◽  
Degree Of Freedom ◽  
Life Extension ◽  
Scale Model ◽  
Design Development ◽  
Seismic Safety ◽  
Six Degrees Of Freedom ◽  
Six Degree Of Freedom

This paper presents the design, development and evaluation of a unique non-contact instrumentation system that can accurately measure the interface displacement between two rigid components in six degrees of freedom. The system was developed to allow measurement of the relative displacements between interfaces within a stacked column of brick-like components, with an accuracy of 0.05 mm and 0.1 degrees. The columns comprised up to 14 components, with each component being a scale model of a graphite brick within an Advanced Gas-cooled Reactor core. A set of 585 of these columns makes up the Multi Layer Array, which was designed to investigate the response of the reactor core to seismic inputs, with excitation levels up to 1 g from 0 to 100 Hz. The nature of the application required a compact and robust design capable of accurately recording fully coupled motion in all six degrees of freedom during dynamic testing. The novel design implemented 12 Hall effect sensors with a calibration procedure based on system identification techniques. The measurement uncertainty was ±0.050 mm for displacement and ±0.052 degrees for rotation, and the system can tolerate loss of data from two sensors with the uncertainly increasing to only 0.061 mm in translation and 0.088 degrees in rotation. The system has been deployed in a research programme that has enabled EDF to present seismic safety cases to the Office for Nuclear Regulation, resulting in life extension approvals for several reactors. The measurement system developed could be readily applied to other situations where the imposed level of stress at the interface causes negligible material strain, and accurate non-contact six-degree-of-freedom interface measurement is required.

scholarly journals Stability and Manoeuvrability Simulation of a Semi-Autonomous Submarine Free-Running Model SUBOFF with an Autopilot System

2021 ◽  
Vol 11 (1) ◽  
pp. 410
Author(s):  
Yu-Hsien Lin ◽  
Yu-Ting Lin ◽  
Yen-Jun Chiu
Keyword(s):  
Optimal Control ◽  
Experimental Tests ◽  
Degree Of Freedom ◽  
Line Of Sight ◽  
Pd Controller ◽  
Free Running ◽  
Simulation Results ◽  
Guidance Algorithm ◽  
Logic Operations ◽  
Six Degree Of Freedom

On the basis of a full-appendage DARPA SUBOFF model (DTRC model 5470), a scale (λ = 0.535) semi-autonomous submarine free-running model (SFRM) was designed for testing its manoeuvrability and stability in the constrained water. Prior to the experimental tests of the SFRM, a six-degree-of-freedom (6-DOF) manoeuvre model with an autopilot system was developed by using logic operations in MATLAB. The SFRM’s attitude and its trim polygon were presented by coping with the changes in mass and trimming moment. By adopting a series of manoeuvring tests in empty tanks, the performances of the SFRM were introduced in cases of three sailing speeds. In addition, the PD controller was established by considering the simulation results of these manoeuvring tests. The optimal control gains with respect to each manoeuvring test can be calculated by using the PID tuner in MATLAB. Two sets of control gains derived from the optimal characteristics parameters were compared in order to decide on the most appropriate PD controller with the line-of-sight (LOS) guidance algorithm for the SFRM in the autopilot simulation. Eventually, the simulated trajectories and course angles of the SFRM would be illustrated in the post-processor based on the Cinema 4D modelling.

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