scholarly journals Design and Structural Analysis of a Control Moment Gyroscope (CMG) Actuator for CubeSats

Aerospace ◽  
2020 ◽  
Vol 7 (5) ◽  
pp. 55
Author(s):  
Alexis Gaude ◽  
Vaios Lappas
Keyword(s):  
Structural Analysis ◽  
Low Cost ◽  
Mechanical Assembly ◽  
Physical Size ◽  
Control Moment Gyroscope ◽  
Control Moment ◽  
Global Trend ◽  
Electronic Board ◽  
Stepper Motors ◽  
Low Mass

Following a global trend towards miniaturization, the population of nano- and micro-satellite continues to increase. CubeSats are standardized small size satellites based on 10 × 10 × 10 cm cube modules (1U) and are becoming sophisticated platforms despite their very small size. This paper details the design and the structural analysis of a Control Moment Gyroscope (CMG) actuator for agile CubeSats with a physical size up to 12U, which require high torque actuators. CMGs have inherited torque amplification capabilities and the recent advances in motor miniaturization make them ideal candidates for small satellite missions with slew rate requirements. The system’s requirements are derived based on conceptual agility requirements for an agile (highly maneuverable) CubeSat which needs to achieve a 90° maneuver in 90 s. With specific cost, mass and volume requirements, the proposed CMG design is based on some of the smallest available off-the-shelf electric motors and uses a light aluminum casing design. The proposed design uses stepper motors for the gimbal mechanism as a low cost, compact and low power solution, contributing to an overall low mass of the full CMG cluster. Static and dynamic analyses were performed to assess the mechanical integrity of the system for launch loads. Apart from a necessary custom control electronic board, the complete mechanical assembly has been designed including electrical hardware. Analyses demonstrate that the overall stress levels acting on the system are manageable by the CMG design. Bolted joints are critical and should be studied independently as the chosen model created singularities around these areas. Each individual CMG of the designed pyramidal cluster is shown to weigh about 35 g. Using the proposed CMG design with a customized avionics board, the complete CMG system is shown to weigh 250 g and occupies slightly more than ½U volume for a CubeSat, indicating the feasibility of CMGs for agile CubeSats.

scholarly journals A Gimballed Control Moment Gyroscope Cluster Design for Spacecraft Attitude Control

Aerospace ◽  
2021 ◽  
Vol 8 (9) ◽  
pp. 273
Author(s):  
Charalampos Papakonstantinou ◽  
Vaios Lappas ◽  
Vassilis Kostopoulos
Keyword(s):  
Attitude Control ◽  
Degrees Of Freedom ◽  
Singularity Avoidance ◽  
Control Moment Gyroscope ◽  
Control Moment ◽  
Control Moment Gyroscopes ◽  
Stepper Motors ◽  
Steering Law ◽  
Commercial Off The Shelf ◽  
A Minor

This paper addresses the problem of singularity avoidance in a cluster of four Single-Gimbal Control Moment Gyroscopes (SGCMGs) in a pyramid configuration when used for the attitude control of a satellite by introducing a new gimballed control moment gyroscope (GCMG) cluster scheme. Four SGCMGs were used in a pyramid configuration, along with an additional small and simple stepper motor that was used to gimbal the full cluster around its vertical (z) axis. Contrary to the use of four variable-speed control moment gyroscopes (VSCMGs), where eight degrees of freedom are available for singularity avoidance, the proposed GCMG design uses only five degrees of freedom (DoFs), and a modified steering law was designed for the new setup. The proposed design offers the advantages of SGCMGs, such as a low weight, size, and reduced complexity, with the additional benefit of overcoming the internal elliptic singularities, which create a minor attitude error. A comparison with the four-VSCMG cluster was conducted through numerical simulations, and the results indicated that the GCMG design was considerably more efficient in terms of power while achieving a better gimbal configuration at the end of the simulation, which is essential when it is desired for different manoeuvres to be consecutively executed. Additionally, for a nano-satellite of a few kilograms, the results prove that it is feasible to manufacture the GCMG concept by using affordable and lightweight commercial off-the-shelf (COTS) stepper motors.

scholarly journals Calibration, Compensation and Accuracy Analysis of Circular Grating Used in Single Gimbal Control Moment Gyroscope

Sensors ◽  
2020 ◽  
Vol 20 (5) ◽  
pp. 1458 ◽  
Author(s):  
Yue Yu ◽  
Lu Dai ◽  
Mao-Sheng Chen ◽  
Ling-Bo Kong ◽  
Chao-Qun Wang ◽  
...  
Keyword(s):  
Low Cost ◽  
Angular Position ◽  
Compensation Method ◽  
Position Measurement ◽  
Control Moment Gyroscope ◽  
Control Precision ◽  
Control Moment ◽  
Single Reading ◽  
Calibration Experiment ◽  
Circular Grating

The accuracy of the circular grating is the key point for control precision of the single gimbal control moment gyroscope servo system used in civilian micro-agile satellites. Instead of using the multi reading heads to eliminate eccentricity errors, an algorithm compensation method based on a calibration experiment using a single reading head was proposed to realize a low-cost and high accuracy angular position measurement. Moreover, the traditional hardware compensation method using double reading heads was also developed for comparison. Firstly, the single gimbal control moment gyroscope system of satellites was introduced. Then, the errors caused by the installation of the reading head were studied and the mathematic models of these errors were developed. In order to construct the compensation function, a calibration experiment using the autocollimator and 24-sided prism was performed. Comparison of angle error compensation using the algorithm and hardware method was presented, and results showed that the algorithm compensation method proposed by this paper achieved the same accuracy level as the hardware method. Finally, the proposed method was further verified through a control system simulation.

scholarly journals Chemical Modification of Combusted Coal Gangue for U(VI) Adsorption: Towards a Waste Control by Waste Strategy

2021 ◽  
Vol 13 (15) ◽  
pp. 8421
Author(s):  
Yuan Gao ◽  
Jiandong Huang ◽  
Meng Li ◽  
Zhongran Dai ◽  
Rongli Jiang ◽  
...  
Keyword(s):  
Structural Analysis ◽  
High Efficiency ◽  
Low Cost ◽  
Chemical Activation ◽  
Cost Effective ◽  
Coal Gangue ◽  
Order Kinetic ◽  
Practical Applications ◽  
Detailed Structural Analysis ◽  
Alkaline Conditions

Uranium mining waste causes serious radiation-related health and environmental problems. This has encouraged efforts toward U(VI) removal with low cost and high efficiency. Typical uranium adsorbents, such as polymers, geopolymers, zeolites, and MOFs, and their associated high costs limit their practical applications. In this regard, this work found that the natural combusted coal gangue (CCG) could be a potential precursor of cheap sorbents to eliminate U(VI). The removal efficiency was modulated by chemical activation under acid and alkaline conditions, obtaining HCG (CCG activated with HCl) and KCG (CCG activated with KOH), respectively. The detailed structural analysis uncovered that those natural mineral substances, including quartz and kaolinite, were the main components in CCG and HCG. One of the key findings was that kalsilite formed in KCG under a mild synthetic condition can conspicuous enhance the affinity towards U(VI). The best equilibrium adsorption capacity with KCG was observed to be 140 mg/g under pH 6 within 120 min, following a pseudo-second-order kinetic model. To understand the improved adsorption performance, an adsorption mechanism was proposed by evaluating the pH of uranyl solutions, adsorbent dosage, as well as contact time. Combining with the structural analysis, this revealed that the uranyl adsorption process was mainly governed by chemisorption. This study gave rise to a utilization approach for CCG to obtain cost-effective adsorbents and paved a novel way towards eliminating uranium by a waste control by waste strategy.

Oscillating Control Moment Gyroscope Experimental Results

2019 ◽  
Author(s):  
Burak Akbulut ◽  
Ozan Tekinalp ◽  
Ferhat Arberkli ◽  
Kivanc Azgin
Keyword(s):  
Experimental Results ◽  
Control Moment Gyroscope ◽  
Control Moment

Low-cost MSI controller for stepper motors

1991 ◽  
Vol 17 (1) ◽  
pp. 63-66 ◽  
Author(s):  
Faisal Fadul ◽  
K. Weidenboerner
Keyword(s):  
Low Cost ◽  
Stepper Motors

Effects of Aluminum Doping on The Phase Stability and Electrochemical Properties of LiCoO2 and LiMnO2

1997 ◽  
Vol 496 ◽  
Author(s):  
Y.-I. Jang ◽  
B. Huang ◽  
H. Wang ◽  
Y.-M. Chiang ◽  
D. R. Sadoway
Keyword(s):  
Single Phase ◽  
Low Cost ◽  
Reversible Capacity ◽  
Open Circuit ◽  
Teller Distortion ◽  
Al Content ◽  
Jahn Teller ◽  
Li Battery ◽  
Low Mass ◽  
Jahn Teller Distortion

ABSTRACTAluminum is of interest as a constituent for Li battery electrodes due to its low cost and low mass, and because ab initio calculations indicate that solid solution of LiAlO2 with LiMO2 (M = transition metal) in the α-NaFeO2 structure can increase intercalation voltage [1]. In this study, we investigated the effect of Al doping on LiCoO2 and LiMnO2. Single phase LiAlyCo1-yO2 has been synthesized up to y = 0.5 by firing homogenous hydroxide precursors. A systematic increase in the open circuit voltage is observed with Al content. In LiAlyMn1-yO2, the addition of LiAlO2 stabilizes LiMnO2 in the α-NaFeO2 structure under conditions where neither endmember is stable in the structure. High reversible capacity was obtained over both a 4 V and 3 V plateau, indicating that the compound transforms to a spinel-related structure during cycling, but that the cooperative Jahn-Teller distortion is suppressed.

Towards Automated Bicycles: Achieving Self-Balance Using Steering Control

2018 ◽  
Author(s):  
Wenhao Deng ◽  
Skyler Moore ◽  
Jonathan Bush ◽  
Miles Mabey ◽  
Wenlong Zhang
Keyword(s):  
Autonomous Vehicles ◽  
Controller Design ◽  
Smart Cities ◽  
Autonomous Driving ◽  
Human Robot Interaction ◽  
Steering Control ◽  
Control Moment Gyroscope ◽  
Control Moment ◽  
Potential Applications ◽  
Electric Bicycle

In recent years, researchers from both academia and industry have worked on connected and automated vehicles and they have made great progress toward bringing them into reality. Compared to automated cars, bicycles are more affordable to daily commuters, as well as more environmentally friendly. When comparing the risk posed by autonomous vehicles to pedestrians and motorists, automated bicycles are much safer than autonomous cars, which also allows potential applications in smart cities, rehabilitation, and exercise. The biggest challenge in automating bicycles is the inherent problem of staying balanced. This paper presents a modified electric bicycle to allow real-time monitoring of the roll angles and motor-assisted steering. Stable and robust steering controllers for bicycle are designed and implemented to achieve self-balance at different forward speeds. Tests at different speeds have been conducted to verify the effectiveness of hardware development and controller design. The preliminary design using a control moment gyroscope (CMG) to achieve self-balancing at lower speeds are also presented in this work. This work can serve as a solid foundation for future study of human-robot interaction and autonomous driving.

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