The PULSAR (Prototype for an Ultra Large Structure Assembly Robot) project, aims at developing and demonstrating core technologies enabling the in-orbit assembly of the 8m-diameter primary mirror of a space telescope with an autonomous robotic system. This paper presents the demonstrator of In-Space Assembly in Simulation, which is designed as an integrated simulation tool for the prototyping and development of these autonomous assembly technologies.

In this paper, the modeling of flexible multi-body systems (typically a satellite), the design of a reduced-order robust controller and the closed-loop system robustness analysis are considered. First, we present a generic tool developed to build the model of a multi- body dynamic system taking into account parametric uncertainties for robust control and analysis purpose. Satellites are typically composed of a main body (hub of the satellite) and cantilevered appendages (flexible or not). Based on the description of each element(mechanical and geometrical properties, uncertain parameters ...), a linear model between torques applied to the hub (control or perturbation inputs) and angular accelerations is built using the Linear Fractional Representation framework. Second, based on this model, a control design method is proposed: from a basic standard scheme and the latest H_infinity solver, a low order H1 controller can be derived. Roll-off requirements and worst-case parametric configurations can also be taken into account in a multi-model design approach. Third, robustness analysis of the design on the full order model is considered. A numerical example illustrate the relevance and effectiveness of the proposed approach.

This paper introduces in cross standard form (CSF) as a solution to the inverse optimal control problem. That is, the CSF is a canonical standard problem whose unique H ∞ or H 2 optimal controller is a given controller. From the control design point of view, the general idea is to apply the CSF to a given controller in order to set up a standard problem which can be completed to handle frequency domain H 2 or H ∞ specification. The analytical formulation of the CSF proposed in this paper can be applied to reduced-, full- or augmented-order compensators or two-degree of freedom compensations. Numerical and academic examples are given.

A particular postsynthesis problem is examined. Assume a first complex controller running on a given system. It turns out that a closed-loop mode is not sufficiently damped. Is it easy to know which adjustable combinations of controller parameters are the most relevant to master this problem? A Bayesian identification procedure is proposed to analyze the relevance of such a given parameter combination with respect to a given modal specification. One application, for which such a controller tuning is very interesting, is the adjustment of flight control laws during flight tests. In this practical context, the observer-based realization of the controller is used to derive an architecture suitable for its implementation, that is, an architecture in which physical tuning parameters can be easily highlighted. The results presented concern the lateral flight control law of a highly flexible aircraft that has been synthesized by a modern robust control approach.