NPSAT1 is a small satellite that employs magnetic sensing and actuation for attitude control. The spacecraft orientation and angular velocity should, therefore, be estimated from the magnetometer readings. The inherent nonlinear dynamics of the system poses a challenging problem on the observer design. This paper demonstrates the ground test results of NPSAT1 state estimation using the Unscented Kalman Filter (UKF) - a fairly recent method with inherent appeals of extended Kalman fllter but with no need for linearization; thus more suitable for highly nonlinear flltering and control applications. The quaternion-based modeling constraint that the quaternion has a unit norm is enforced by treating the norm of the quaternion as a dummy measurement. The experimental results show the superior performance of the UKF in practice.
{"title":"Unscented Kalman Filtering: NPSAT1 Ground Test Results","authors":"P. Sekhavat, Q. Gong, I. Michael Ross","doi":"10.2514/6.2006-6352","DOIUrl":"https://doi.org/10.2514/6.2006-6352","url":null,"abstract":"NPSAT1 is a small satellite that employs magnetic sensing and actuation for attitude control. The spacecraft orientation and angular velocity should, therefore, be estimated from the magnetometer readings. The inherent nonlinear dynamics of the system poses a challenging problem on the observer design. This paper demonstrates the ground test results of NPSAT1 state estimation using the Unscented Kalman Filter (UKF) - a fairly recent method with inherent appeals of extended Kalman fllter but with no need for linearization; thus more suitable for highly nonlinear flltering and control applications. The quaternion-based modeling constraint that the quaternion has a unit norm is enforced by treating the norm of the quaternion as a dummy measurement. The experimental results show the superior performance of the UKF in practice.","PeriodicalId":254469,"journal":{"name":"AIAA Guidance, Navigation, and Control Conference and Exhibit","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127457322","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this paper we present an approach for combined fault diagnosis and reconfigurable control structure for a general class of hybrid systems. In this approach a plant is modeled using an extended version of bond graphs, namely hybrid bond graph, where discrete mode transitions are represented as binary switch junctions. A hybrid observer has been developed that uses this model to track the system behavior within and across modes. Two complementary approaches are used for fault detection and isolation. The first diagnoser is based on hybrid models and uses the hybrid observer, qualitative reasoning techniques, and real-time parameter estimation. The other diagnoser is based an
{"title":"Integrated Diagnosis and Control for Hybrid Dynamic Systems","authors":"G. Karsai, S. Abdelwahed, Gautam Biswas","doi":"10.2514/6.2003-5673","DOIUrl":"https://doi.org/10.2514/6.2003-5673","url":null,"abstract":"In this paper we present an approach for combined fault diagnosis and reconfigurable control structure for a general class of hybrid systems. In this approach a plant is modeled using an extended version of bond graphs, namely hybrid bond graph, where discrete mode transitions are represented as binary switch junctions. A hybrid observer has been developed that uses this model to track the system behavior within and across modes. Two complementary approaches are used for fault detection and isolation. The first diagnoser is based on hybrid models and uses the hybrid observer, qualitative reasoning techniques, and real-time parameter estimation. The other diagnoser is based an","PeriodicalId":254469,"journal":{"name":"AIAA Guidance, Navigation, and Control Conference and Exhibit","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115810294","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Station-keeping and reorientation control ofa cluster off ully-actuated low-thrust micro-satellites is considered in this paper. We propose a very general optimization based control methodology to solve constrained trajectory generation problems for stationkeeping and reorientation. By taking advantage ofthe f ully-actuated structure ofthe micro-satellite, it is possible to compute the control on-board the micro-satellites. Performance of this methodology is reported for a typical micro-satellite formation flying space mission using the Nonlinear Trajectory Generation software package.
{"title":"Constrained trajectory generation for micro-satellite formation flying","authors":"Mark B. Milam, N. Petit, R. Murray","doi":"10.2514/6.2001-4030","DOIUrl":"https://doi.org/10.2514/6.2001-4030","url":null,"abstract":"Station-keeping and reorientation control ofa cluster off ully-actuated low-thrust micro-satellites is considered in this paper. We propose a very general optimization based control methodology to solve constrained trajectory generation problems for stationkeeping and reorientation. By taking advantage ofthe f ully-actuated structure ofthe micro-satellite, it is possible to compute the control on-board the micro-satellites. Performance of this methodology is reported for a typical micro-satellite formation flying space mission using the Nonlinear Trajectory Generation software package.","PeriodicalId":254469,"journal":{"name":"AIAA Guidance, Navigation, and Control Conference and Exhibit","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121049721","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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