Modified L1 Adaptive Control Design for Satellite FMC Systems with Actuators Time Delay


Department of Aerospace Engineering, Malek-Ashtar University of Technology, Tehran, Iran


A modified method for satellite attitude control system in presence of novel actuators is proposed in this paper. The attitude control system is composed of three fluidic momentum controller (FMC) actuators that are used to control Euler angles and their dynamics is considered in satellite attitude equations as well. L1 adaptive control is utilized for satellite three-axial stabilization. A significant characteristic of L1 adaptive control structure is that robustness is guaranteed in presence of fast adaptation. The main achievement of this controller is that the error norm is inversely proportional to the square root of adaptation gains. Therefore, large values of gains provides some advantages. The proposed L1 adaptive control is designed based on simplified attitude dynamic equations without satellite coupling effects, and then it is placed on coupled nonlinear equations. Next, the impact of available delay on FMC actuators is investigated. Simulation results suggest that the system remains stable with the assumption of actuators time delay, but it experiences some oscillations in Euler angles, control inputs and angular velocities. In order to solve this problem, a modified L1 adaptive control system including a predictive observer with high estimation speed is used. Finally, it is recognized that the available oscillations are reduced even when the actuator time delay increases and thus the control system’s performance improves.


1.  Avanzini, G., Capello, E., Piacenza, I.A. and Quagliotti, F., Hovakimyan, N., Xargay, E.,"L1 Adaptive Control of  Flexible Aircraft: Preliminary Results", AIAA Atmospheric Flight Mechanics Conference 2010, Toronto, Ontario Canada, (2010).
2.  Cao, C., and Hovakimyan, N., “L1 Adaptive Control for Safety-Critical Systems”,IEEE Control Systems Journal, Vol. 31,  (2011), 54-104.
3.   Cao, C.,  and Hovakimyan, N., "Design and Analysis of a Novel L1 Adaptive Controller", Part I: Control Signal and Asymptotic Stability, American Control Conference 2006, Minneapolis, Minnesota, USA, (2006).
4.   Cao, C., and Hovakimyan, N., "Design and Analysis of a Novel L1 Adaptive Controller", Part II: Guaranteed Transient Performance, American Control Conference, 2006, Minneapolis, Minnesota, USA, (2006).
5.   Kharisov, E., Gregory, I.M., Cao, C., and Hovakimyan, N., "L1 Adaptive Control Law for Flexible Launch Vehicle and Proposed Plan for Flight Test Validation", AIAA Guidance, Navigation and Control Conference 2008, Honolulu, Hawaii, USA, (2008).
6.  Hovakimyan, N., and Cao, C., "L1 Adaptive Control Theory: Guaranteed Robustness with Fast Adaptation",  Society for Industrial and Applied Mathematics, SIAM publisher, (2010).
7.   Kharisov, E., and Hovamikian, N., "L1 Adaptive Output Feedback Controller for Minimum Phase Systems",American Control Conference, 2011, San Francisco, CA, USA, (2011).
8.   Kim, K.K., and Hovamikian, N., “Multi-Criteria Optimization for Filter of  L1 Adaptive Control”,Journal of Optimimm Theory Applied, Vol. 161, (2014), 557–581.
9.   Lee, K.W., Singh, S.N., “L1 Adaptive Control of Flexible Spacecraft Despite Disturbance”,Acta Astronautica, Vol. 80, (2012), 24-35.
10.  Elahidoost, A., Cooper, J., Cao, C., and Pham, K., "Satellite Orbit Stabilization Using L1 Adaptive Control",AIAA Guidance, Navigation and Control Conference 2012, Minneapolis, Minnesota, USA, (2012).
11.  Vogel, H., Fichter, W., and Choe, R., Xargay, E., Hovakimyan, N., "Magnetic Momentum Control of a Satellite Augmented with an L1 Adaptive Control",AIAA Guidance, Navigation, and Control Conference, 2013, Boston, MA, USA, (2013).
12.  Maynard, R.S., "Fluid Momentum Control", U.S. Patent 4, 776, 541, (1988).
13.  Lurie, B.J., and Schier, J.A., "Liquid-Ring Attitude Control System for Spacecraft", NASA Tech Briefs, 14, 92, (1990).
14. Iskenderian, T.C., "Liquid Angular Momentum Compensator", NASA Tech. Briefs, (1989).
15. Laughlin, D.R., Sebesta, H.R., and Ckelkamp-Baker, D.E., “A Dual Function Magnetohydrodynamic (MHD) Device for Angular Motion Measurement and Control”, Advances in the Astronautical Sciences, Vol. 111, (2002), 335-348.
16. Kelly, A.C., Mc Chesney, C., Smith, P.Z., and Waltena, S., "A Performance Test of A Fluidic Momentum Controller in Three Axes", NASA Report, (2004).
17. Kumar, K.D., “Satellite Attitude Stabilization Using Fluid Rings”, Acta Mechanica, Vol. 208, No. 2, (2009), 117–131.
18. Varatharajoo, R., Kahle, R., and Fasoulas, S., “Approach for Combining Spacecraft Attitude and Thermal Control Systems”, Journal of Spacecraft and Rocket, Vol. 40, No. 5, (2003), 657-664.
19. Alkhodari, S.B., and Varatharajoo, R., “H2 and H Control Options for the Combined Attitude and Thermal Control System (CATCS)”, Advances in Space Research, Vol. 43, (2009), 1897-1903.
20. Nobari, N.A., Misra, A.K., "Satellite Attitude Stabilization Using Four Fluid Rings in a Pyramidal Configuration", AIAA/AAS Astrodynamics Specialist Conference,  Aug. 2010, Toronto, Canada, (2010).
21. Nobari, N.A., and Misra, A.K., “Attitude Dynamics and Control of Satellites with Fluid Ring Actuators”, Journal of Guidance, Control and Dynamics (AIAA), Vol. 35, No. 6, (Nov-Dec 2012), 1855-1864.
22. Nobari, N.A., and Misra, A.K., “A Hybrid Attitude Controller Consisting of Electromagnetic Torque Rods and an Active Fluid Ring”, Acta Astronautica, Vol. 94, (2014), 470-479.
23. Taghavi, A.H., Soleymani, A., and Shojaee, T., “Attitude Control System Design Based on Fluidic Momentum Controllers under Adaptive Sliding Mode”, Journal of Space Science and Technology, Vol. 7, No. 2, (2014), 63-74, (In persian).
24. Tayebi, J., and Soleymani, A., "A comparative study of CMG and FMC actuators for Nano satellite attitude control system-pyramidal configuration", 7th International Conference on Recent Advances in Space Technologies (RAST), 16-19 June 2015, Istanbol, Turkey, (2015).
25. Nosratollahi, M., Soleymani, A., and Sadati, S.H., “Design of Satellite’s Combined Attitude and Thermal Control System Equipped with FMC Actuators”, Modares Mechanical Engineering, Vol. 18, No. 1, (2018), 122-130, (In persian).
26.  Cao, C., and Hovakimyan, N., “L1 Adaptive Controller for systems with Unknown Time-varying Parameters and Disturbances in the Presence of Non-zero Trajectory Initialization Error”, International Journal of Control, Vol. 81, (2008), 1147–1161.