The SPHERES Navigation System: from Early Development to On-Orbit Testing

Nolet, Simon

doi:10.2514/6.2007-6354

Cited by 31 publications

(21 citation statements)

References 10 publications

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“…It was successfully implemented and tested at the Synchronized Position Hold Engage and Reorient Experimental Satellites (SPHERES) facility at the Massachusetts Institute of Technology Space Systems Laboratory [41]. This successful ground testing enabled execution of SPHERES flight testing inside the International Space Station (ISS) [20].…”

Section: Discussionmentioning

confidence: 99%

Autonomous Distributed Control of Simultaneous Multiple Spacecraft Proximity Maneuvers

McCamish

Romano

Yun

2010

IEEE Trans. Automat. Sci. Eng.

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Abstract-An autonomous distributed control algorithm for multiple spacecraft performing simultaneous close proximity maneuvers has been developed. Examples of these maneuvers include automated on-orbit inspection, assembly, or servicing. The proposed control algorithm combines the control effort efficiency of the Linear Quadratic Regulator (LQR) and the robust collision avoidance capability of the Artificial Potential Function (APF) method. The LQR control effort serves as the attractive force toward goal positions, while APF-based repulsive functions provide collision avoidance for both fixed and moving obstacles. Comprehensive validation and performance evaluation of the control algorithm is conducted by numerical simulations. The simulation results show the developed LQR/APF algorithm to be both robust and efficient for controlling multiple spacecraft during simultaneous docking maneuvers.Note to Practitioners-Use of multiple spacecraft for close proximity operations is expected to increase in future space missions. A challenging problem is how to automate motion planning and control of multiple spacecraft in close proximity. This paper presents a distributed control algorithm for simultaneous docking maneuvers of multiple spacecraft.

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Section: Discussionmentioning

confidence: 99%

Autonomous Distributed Control of Simultaneous Multiple Spacecraft Proximity Maneuvers

McCamish

Romano

Yun

2010

IEEE Trans. Automat. Sci. Eng.

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“…These data combined with data from three gyroscopes are processed using the navigation software module to compute a 6-DOF state solution. The resulting precision on the estimates is a few millimeters in position and approximately 1 deg in attitude in most of the testing volume [37]. When using a control frequency of typically 1 Hz (adjustable), the satellites can maintain a position uncertainty of 2 cm inside of the testing volume, even when neglecting the orbital dynamics.…”

Section: Overview Of the Mit Spheres Facilitymentioning

confidence: 95%

“…6) is executed in parallel of the SPHERES standard attitude controller at a control frequency of 1 Hz. It uses navigation information provided by onboard sensor data (gyroscopes and ultrasonic sensors) processed with an extended Kalman filter [37]. Navigation states of neighboring spacecraft are provided wirelessly through simulated communication to simulate remote sensing capabilities.…”

Section: Implementation In the Mit Spheres Matlab Simulationmentioning

confidence: 99%

Flight Testing of Multiple-Spacecraft Control on SPHERES During Close-Proximity Operations

McCamish¹,

Romano²,

Nolet³

et al. 2009

Journal of Spacecraft and Rockets

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A multiple-spacecraft close-proximity control algorithm was implemented and tested with the Synchronized Position Hold Engage and Reorient Experimental Satellites (SPHERES) facility onboard the International Space Station. During flight testing, a chaser satellite successfully approached a virtual target satellite while avoiding collision with a virtual obstacle satellite. This research contributes to the control of multiple spacecraft for emerging missions, which may require simultaneous gathering, rendezvous, and docking. The unique control algorithm was developed at the U.S. Naval Postgraduate School and integrated onto the Massachusetts Institute of Technology's SPHERES facility. The control algorithm implemented combines the efficiency of the linear quadratic regulator (used for attraction toward goal positions) and the robust collision-avoidance capability of the artificial potential field method (used for repulsion from moving obstacles). The amalgamation of these two control methods into a multiple-spacecraft close-proximity control algorithm yielded promising results, as demonstrated by simulations. Comprehensive simulation evaluation enabled implementation and ground testing of the spacecraft control algorithm on the SPHERES facility. Successful ground testing led to the execution of flight experiments onboard the International Space Station, which demonstrated the proposed algorithm in a microgravity environment. NomenclatureA, B, C = state-space matrices a = acceleration due to linear-quadratic-regulator-and artificial-potential-field-determined control effort a APF = acceleration due to artificial-potential-fielddetermined control effort a LQR = acceleration due to linear-quadratic-regulatordetermined control effort a m = maximum acceleration a obs = acceleration of chaser spacecraft toward an obstacle a x;y;z = acceleration due to the control effort

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“…Each SPHERES satellite has twelve thrusters, fueled by a single CO 2 tank, for full six degrees of freedom actuation [6]. The satellites use an Extended Kalman Filter (EKF) for estimation, using primarily time of flight measurements from the ultrasound beacons and receivers, as well as gyroscopes [7]. The nominal control architecture is a mix of Proportional-Derivative (PD) and Proportional-IntegralDerivative (PID) controllers.…”

Section: Spheres Overviewmentioning

confidence: 99%

SPHERES Reconfigurable Framework and Control System Design for Autonomous Assembly

Mohan

Miller

2009

AIAA Guidance, Navigation, and Control Conference

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Abstract:Reconfigurable control system design is a key component for enabling autonomous on-orbit assembly. Current research on reconfigurable control systems focuses on adapting to failures. However, for assembly scenarios, the reconfiguration is necessitated by changing mass and stiffness properties. This paper provides a brief description of existing reconfigurable control system technology and develops a framework to incorporate reconfiguration into an existing baseline system to account for mass property variations. The reconfigurable control system framework has been developed and implemented using the SPHERES (Synchronized Position Hold Engage Reorient Experimental Satellites) testbed as the baseline system. The framework highlights the elements that need to be updated, introduces a variable p that captures the configuration, and details the updates necessary in the key algorithms to calculate the model online using p. Results are presented from the implementation on the SPHERES, focusing on the reconfigurable estimator. Plans are presented for an integrated assembly test that demonstrates the maintenance of stability, fuel efficiency, and accuracy throughout configuration changes that occur during assembly. Introduction:Reconfigurable control systems are used in a variety of applications, such as docking, servicing, high efficiency flight, and assembly. Autonomous assembly is a critical technology for future missions such as large space telescopes, on-orbit space stations, and a lunar base. One particular scenario for autonomous on-orbit assembly is to use an assembler tug to maneuver the different payload items. In this scenario, the dynamics of the assembler tug will vary greatly at each docking and undocking maneuver, based on the properties of the payload, such as mass and inertia. Depending on the relative sizes of the tug to the payload, this could be a very significant change. In order to maintain adequate control performance, it is important to account for the property changes. The implementation of a reconfigurable control system would be able to account for the frequent mass property changes, while also introducing adaptability into the system design. The sequence of assembly would not need to be pre-determined, nor would all configurations have to be pre-computed.

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The SPHERES Navigation System: from Early Development to On-Orbit Testing

Cited by 31 publications

References 10 publications

Autonomous Distributed Control of Simultaneous Multiple Spacecraft Proximity Maneuvers

Autonomous Distributed Control of Simultaneous Multiple Spacecraft Proximity Maneuvers

Flight Testing of Multiple-Spacecraft Control on SPHERES During Close-Proximity Operations

SPHERES Reconfigurable Framework and Control System Design for Autonomous Assembly

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