Motivated by several accidents, attitude control of a spacecraft subject to faults/failures has gained considerable attention in a wider range of aerospace engineering and academic communities. This paper is concerned with industrial practices and theoretical approaches for fault tolerant control (FTC) and fault detection and diagnosis (FDD) in spacecraft attitude control system. An overview on recent development of spacecraft attitude FTC system design is presented. The basis of a FTC system is introduced. The existing engineering FTC techniques and theoretical methodologies, including their advantages and disadvantages, are discussed. Moreover, closely associated with the reliability-relevant issues, recent progress in attitude FTC design strategies is reviewed. A brief review of some open problems in the general area of spacecraft attitude control design subject to components faults/failures is further concluded.

A Review on Recent Development of Spacecraft Attitude Fault Tolerant Control System

Bayesian Networks and Influence Diagrams: A Guide to Construction and Analysis

We present a satellite attitude control system design using low-cost hardware and software for a 1U CubeSat. The attitude control system architecture is a crucial subsystemfor any satellite mission since precise pointing is often required to meet mission objectives. The accuracy and precision requirements are even more challenging for small satellites where limited volume, mass, and power are available for the attitude control system hardware. In this proposed embedded attitude control system design for a 1U CubeSat, pointing is obtained through a two-stage approach involving coarse and fine control modes. Fine control is achieved through the use of three reaction wheels or three magnetorquers and one reaction wheel along the pitch axis. Significant design work has been conducted to realize the proposed architecture. In this paper, we present an overview of the embedded attitude control system design; the verification results fromnumerical simulation studies to demonstrate the performance of a CubeSat-class nanosatellite; and a series of air-bearing verification tests on nanosatellite attitude control systemhardware that compares the performance of the proposed nonlinear controller with a proportional-integral-derivative controller.

https://downloads.hindawi.com/journals/jcse/2013/657182.pdf

Design of attitude control systems for cubesat-class nanosatellite

Tensegrity structures provide both structural integrity and flexibility through the combination of stiff struts and a network of flexible tendons. These structures exhibit useful properties: high stiffness-to-mass ratio, controllability, reliability, structural flexibility, and large deployment. The integration of smart materials into tensegrity structures would provide additional functionality and may improve existing properties. However, manufacturing approaches that generate multimaterial parts with intricate three-dimensional (3D) shapes suitable for such tensegrities are rare. Furthermore, the structural complexity of tensegrity systems fabricated through conventional means is generally limited because these systems often require manual assembly. Here, we report a simple approach to fabricate tensegrity structures made of smart materials using 3D printing combined with sacrificial molding. Tensegrity structures consisting of monolithic tendon networks based on smart materials supported by struts could be realized without an additional post-assembly process using our approach. By printing tensegrity with coordinated soft and stiff elements, we could use design parameters (such as geometry, topology, density, coordination number, and complexity) to program system-level mechanics in a soft structure. Last, we demonstrated a tensegrity robot capable of walking in any direction and several tensegrity actuators by leveraging smart tendons with magnetic functionality and the programmed mechanics of tensegrity structures. The physical realization of complex tensegrity metamaterials with programmable mechanical components can pave the way toward more algorithmic designs of 3D soft machines.

3D-printed programmable tensegrity for soft robotics.

Agile satellites with advanced attitude maneuvering capability are the new generation of earth observation satellites (EOSs). The continuous improvement in satellite technology and decrease in launch cost have boosted the development of agile EOSs (AEOSs). To efficiently employ the increasing orbiting AEOSs, the AEOS scheduling problem (AEOSSP) aiming to maximize the entire observation profit while satisfying all complex operational constraints, has received much attention over the past 20 years. The objectives of this article are, thus, to summarize current research on AEOSSP, identify main accomplishments and highlight potential future research directions. To this end, general definitions of AEOSSP with operational constraints are described initially, followed by its three typical variations including different definitions of observation profit, multiobjective function and autonomous model. A detailed literature review from 1997–2019 is then presented in line with four different solution methods, i.e., exact method, heuristic, metaheuristic, and machine learning. Finally, we discuss a number of topics worth pursuing in the future.

Agile Earth Observation Satellite Scheduling Over 20 Years: Formulations, Methods, and Future Directions

We present a musical keyboard that is not only velocity-sensitive, but in fact responds to absement (presement), displacement (placement), velocity, acceleration, jerk, jounce, etc. (i.e. to all the derivatives, as well as the integral, of displacement).Moreover, unlike a piano keyboard in which the keys reach a point of maximal displacement, our keys are essentially infinite in length, and thus never reach an end to their key travel. Our infinite length keys are achieved by using water jet streams that continue to flow past the fingers of a person playing the instrument. The instrument takes the form of a pipe with a row of holes, in which water flows out of each hole, while a user is invited to play the instrument by interfering with the flow of water coming out of the holes. The instrument resembles a large flute, but, unlike a flute, there is no complicated fingering pattern. Instead, each hole (each water jet) corresponds to one note (as with a piano or pipe organ). Therefore, unlike a flute, chords can be played by blocking more than one water jet hole at the same time. Because each note corresponds to only one hole, different fingers of the musician can be inserted into, onto, around, or near several of the instrument's many water jet holes, in a variety of different ways, resulting in an ability to independently control the way in which each note in a chord sounds.Thus the hydraulophone combines the intricate embouchure control of woodwind instruments with the polyphony of keyboard instruments.Various forms of our instrument include totally acoustic, totally electronic, as well as hybrid instruments that are acoustic but also include an interface to a multimedia computer to produce a mixture of sounds that are produced by the acoustic properties of water screeching through orific plates, as well as synthesized sounds.

/pdf/hydraulophone-design-considerations-absement-displacement-3qllm77oin.pdf

Hydraulophone design considerations: absement, displacement, and velocity-sensitive music keyboard in which each key is a water jet

This paper presents the development of low-cost methodologies to determine the attitude of a small, CubeSat-class satellite and a microrover relative to the sun's direction. The use of commercial hardware and simple embedded designs has become an effective path for university programs to put experimental payloads in space for minimal cost, and the development of sensors for attitude and heading determination is often a critical part. The development of two compact and efficient but simple coarse sun sensor methodologies is presented in this research. A direct measurement of the solar angle uses a photodiode array sensor and slit mask. Another estimation of the solar angle uses current measurements from orthogonal arrays of solar cells. The two methodologies are tested and compared on ground hardware. Testing results show that coarse sun sensing is efficient even with minimal processing and complexity of design for satellite attitude determination systems and rover navigation systems.

https://downloads.hindawi.com/journals/ijae/2013/549080.pdf

A Low-Cost Photodiode Sun Sensor for CubeSat and Planetary Microrover

This paper provides a comprehensive review of the development of Collaborative Mobile Industrial Manipulator (CMIM), which is currently in high demand. Such a review is necessary to have an overall understanding about CMIM advanced technology. This is the first review to combine the system architecture and application which is necessary in order to gain a full understanding of the system. The classical framework of CMIM is firstly discussed, including hardware and software. Subsystems that are typically involved in hardware such as mobile platform, manipulator, end-effector and sensors are presented. With regards to software, planner, controller, perception, interaction and so on are also descripted. Following this, the common applications (logistics, manufacturing and assembly) in industry are surveyed. Finally, the trends are predicted and issues are indicated as references for CMIM researchers. Specifically, more research is needed in the areas of interaction, fully autonomous control, coordination and standards. Besides, experiments in real environment would be performed more and novel collaborative robotic systems would be proposed in future. Additionally, some advanced technology in other areas would also be applied into the system. In all, the system would become more intelligent, collaborative and autonomous.

/pdf/collaborative-mobile-industrial-manipulator-a-review-of-1j7t2d9k4k.pdf

Mark Post

Papers

Design of attitude control systems for cubesat-class nanosatellite

Hydraulophone design considerations: absement, displacement, and velocity-sensitive music keyboard in which each key is a water jet

A Low-Cost Photodiode Sun Sensor for CubeSat and Planetary Microrover

Collaborative mobile industrial manipulator: A review of system architecture and applications

Modularity for the future in space robotics : a review