two main contributions of this paper are:

-   the idea of adding redundant switching times in order to make a nominal bang-bang control more robust, while keeping it as being bang-bang;

-   the design of a practical tracking algorithm, consisting of solving an overdetermined nonlinear system by least-squares, thus identifying a robustness criterion that we optimize.

They are developed in a rigorous and general context in the core of the paper.

State of the art on robust control design
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There is an immense literature on robust control theory, with many existing methods in order to efficiently control a system subjected to uncertainties and disturbances. Whereas there are many papers on $\mathcal{H}_2$ and $\mathcal{H}_{\infty}$ methods, except a few contributions in specific contexts, we are not aware of any general theory allowing one to tackle perturbations by using only bang-bang controls. This is the focus of this paper.

Let us however shortly report on robustness methods when one is not bound to design bang-bang controls. In [@Koh:1999], a path-tracking algorithm with bang-bang controls is studied, for a double integrator and a wheeled robot. The technique relies heavily on the expression of the equations and does not apply to more general systems. 