English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

We obviate the use of observers for the purpose of output feedback trackingcontrol of Lagrangian systems and solve some long-standing yet well-documentedopen problems. As often implemented in control practice, we replace unavailablederivatives with approximate differentiation. Our contribution consists inestablishing uniform global asymptotic stability in closed-loop, for Lagrangiansystems without dissipative forces (friction) using only position feedback.Firstly, for fully-actuated relative-degree-two systems, the controller isreminiscent of passivity-based controllers for robot manipulators and consistsin a linear dynamic system together with a globally-Lipschitz control law.Establishing a global uniform result, all the more with such a simplecontroller, is particularly valuable relatively to the literature ofoutput-feedback control of systems with non-globally-Lipschitz nonlinearitiesin the unmeasured variables. This first contribution solves a long-standingopen problem and, as a matter of fact, recasted in a general context thisresult is at the edge of what is achievable -see [24]. Then, we show that ourcontrol approach may be applied to a more general problem, that of trackingcontrol of Lagrangian systems augmented by a chain of integrators (withrelative degree greater than two). As a corollary, we solve the global-trackingposition-feedback control problem for flexible-joint robots but also forsystems coupled with output-feedback linearizable actuator dynamics. Finally,we discuss remaining open problems of fairly general interest in the realm ofanalysis and design of robust nonlinear systems.

Observer-less Output Feedback Global Tracking Control of Lossless Lagrangian Systems