Formation Feedback Applied to Behavior-Based Approach to Formation Keeping

Approaches to the study of formation keeping for multiple mobile robots are analyzed and a behavior-based robot model is built in this paper. And, a kind of coordination architecture is presented, which is similar to the infantry squad organization and is used to realize multiple mobile robots to keep formations. Simulations verify the validity of the approach to keep formation, which combines the behavior-based method and formation feedback. The effects of formation feedback on the performance of the system are analyzed.

Formation keeping control through inter-satellite electromagnetic force

Satellite formation keeping through inter-satellite electromagnetic force provides an attractive alternative for future space missions due to its distinct advantages of no propellant consumption or plume contamination as compared to conventional approaches.However,the internal force nature as well as the high nonlinearity and coupling of electromagnetic force brings new control challenges for this novel technique.In this paper,analysis on the dynamics characteristics and special control issues in the presence of electromagnetic force is carried out on the basis of the derived relatively translational dynamics.Considering the model uncertainties,external disturbances and sensor noise,a combined nonlinear control scheme involving feed-forward and feedback control components is proposed for electromagnetic-force-based formation keeping.The feed-forward component is directly obtained through desired configuration and dynamics under nominal conditions while the feedback component is realized utilizing active disturbance rejection control methodology with some reasonable improvement.Numerical simulation is presented to verify the feasibility and validity of the combined control scheme.

Switching LPV control for electromagnetic formation flying on highly elliptical orbit

The electromagnetic force generated by the interaction of electromagnetic coils can be used to replace the conventional propellant consumption mode in close relative motion control,thereby promoting the application of formation flight technology for long-term and continuous space missions.Herein,a hysteresis-switching logic-based switching linear parameter varying(LPV)controller synthesis technique with guaranteed performance for electromagnetic formation flying on a highly elliptical orbit is proposed.First,considering that the relative dynamics model of an elliptical orbit is characterized by time-varying uncertainty,the LPV model is described.By introducing switching LPV controllers among different scheduled parameter subsets,conservativeness can be reduced.Second,the system modeling error,the uncertainty caused by a simplified electromagnetic coil model,and external disturbance are considered to derive switching LPV controller synthesis conditions based on the guaranteed H_(∞)performance.Derivation analysis shows that the proposed switching LPV controller not only ensures the robustness of the system against uncertainties,but also realizes the control input constraints.Finally,numerical simulations and comparative analyses are performed to demonstrate the effectiveness and advantages of the proposed control method.