Attitude tracking control of a flexible spacecraft under angular velocity constraints

Abstract

In this paper, a new technique is proposed for trajectory tracking of a flexible spacecraft subject to angular velocity constraints. The problem is addressed using an Output to Input Saturation Transformation (OIST) which converts the prescribed bounds into state-dependent saturations on the control input signals. It is shown that an interval observer can be used in combination with the OIST technique to ensure that the constraints remain satisfied despite unmeasured flexible modes and torque disturbances. Some realistic simulations conclude the paper and validate our approach.

Spacecraft Attitude Control With Nonconvex Constraints: An Explicit Reference Governor Approach

“…Given the combined potential function P (v, r) = Pr(v, r) + Pe(v), it follows by construction that the dynamic system (28) is such thaṫ…”

“…Following from (30), any point belonging to the manifold S1 is such that ρr(v, r) + ρe(v) is parallel to ρr(v, r). Therefore, system (28) will remain in the manifold and will necessarily converge to s1 ∈ S1 due to the time-decreasing properties of P (v(t)) and the fact that r / ∈ S1. Consider now the case v = ws1, where the quaternion w ∈ Q satisfying wR = cos ε 2 , wI ⊥ ĥR(s1)e1 represents an infinitesimal rotation of ε > 0 away from the manifold S1.…”

“…Finally, anti-windup schemes can be used to augment a nominal control to deal with control saturation [27] and/or output constraints [28]. Although these methods are attractive to practitioners since they do not modify the nominal control law, addressing multiple exclusion cone constraints with this approach can be very challenging.…”

Robust model reference control for uncertain second-order system subject to parameter uncertainties

“…However, in some practical situation, second-order systems capture the dynamic behaviours of many natural phenomena. For this reason, the research for second-order systems with parameter uncertainties has received more and more attention (Burlion et al, 2019; Duan and Huang, 2008; Li et al, 2019; Ranatunga et al, 2017; Rashidi et al, 2015).…”