Local-homogeneity-based global continuous control for mechanical systems with constrained inputs: finite-time and exponential stabilisation

"A global continuous control scheme for the finite-time or (local) exponential stabilisation of mechanical systems with constrained inputs is proposed. The approach is formally developed within the theoretical framework of local homogeneity. This has permitted to solve the formulated problem not only guaranteeing input saturation avoidance but also giving a wide range of design flexibility. The proposed scheme is characterised by a saturating-proportional-derivative type term with generalised saturating and locally homogeneous structure that permits multiple design choices on both aspects. The work includes a simulation implementation section where the veracity of the so-cited argument claiming that finite-time stabilisers are faster than asymptotical ones is studied. In particular, a way to carry out the design so as to, indeed, guarantee faster stabilisation through finite-time controllers (beyond their finite-time convergence) is shown.

Efecto de la topología del tren de potencia en la vida de las baterías

Tesis (Maestría en Control y Sistemas Dinámicos)"El trabajo de tesis Efecto de la topología del tren de potencia en la vida de las baterías tiene la finalidad de evaluar el desempeño de las baterías en función del tren de potencia del vehículo en el que son utilizadas; en particular su tiempo, su temperatura y corriente demandada. Las topologías del tren de potencia utilizadas en en análisis incluyen ultracapacitores y convertidores de potencia. El análiss de las topologías toma en cuenta modelos dinámicos eléctricos del ultracapacitor y la batería, así como modelos de temperatura y tiempo de vida. Se obtienen guías de dimensionesmiento de componentes con base en el análisis dinámico de demanda y la potencia demandada por el ciclo de manejo; además en el criterio se consideran los voltajes y corrientes máximos de cada dispositivo. A partir del análisis realizado y el criterio de diseño obtenido, se realizan simulaciones numéricas de cada topología considerando diferentes patrones de manejo con el fin de evaluar el desempeño de las baterías y de la topología en función del ciclo de conducción. El análisis realizado de esta manera constituye la aportación principal de la tesis, misma que no existe en la literatura.""The aim of this work is to evaluate the battery performance as a function of the vehicle power train. The life cycle, temperature and maximum current demanded are the main aspects that are taken into account in the evaluation. The power train topologies studied in this analysis include ultracapacitors and power converters; moreover, electric dynamic models of the ultracapacitors and batteries are used. Design guidelines are derived from the dynamic analysis of the power demand as a function of the driving cycle and they include the operation restrictions of the energy storage system as the maximum operation voltage and current. The proposed design guidelines along with the performed analysis are evaluated using numerical simulation in every topology for different driving cycles. This analysis constitutes the main contribution of this thesis, which does not have a precedent in the literature.

Observer-less output-feedback global continuous control for the finite-time and exponential stabilization of mechanical systems with constrained inputs

"An observer-less output-feedback global continuous control scheme for the finite-time or (local) exponential stabilization of mechanical systems with constrained inputs is proposed. The approach is formally developed within the theoretical framework of local homogeneity. The closed-loop analysis incorporates a complementary insight on the control-induced motion dissipation through an ad hoc feedback-system passivity theorem. The work includes a simulation implementation section where the performance difference of the proposed scheme with previous observer-based and differentiation algorithms is brought to the fore.

Output-feedback global continuous finite-time and exponential stabilization of bounded-input mechanical systems

"This work proposes an output-feedback global continuous controller for the finite-time or (local) exponential stabilization of bounded-input mechanical systems. The control design is carried out within the analytical framework of local homogeneity. The proposed approach avoids velocity measurements on the feedback through the use of a dynamic dissipator expressed in a generalized non-linear form. The analytical results are supported through simulation tests. In particular, such implementations show the performance differences obtained through diverse particular dynamic dissipator structures, as well as the contrast among the finite-time and exponential convergence achievable through the proposed scheme.

An output-feedback global continuous control scheme with desired gravity compensation for the finite-time and exponential regulation of bounded-input robotic systems

"A Saturating-Proportional Saturating-Derivative type global continuous control scheme with desired gravity compensation for the finite-time or (local) exponential stabilization of robotic systems with constrained inputs, avoiding velocity variables in the feedback, is presented. The proposed output-feedback controller proves to need a closed-loop analysis with considerably higher degree of complexity, and entail more involved consequent requirements, than in the on-line compensation case. Other analytical limitations are further overcome through the developed algorithm. Simulation tests corroborate the efficiency of the proposed approach.