Modeling and Tip Position Control of a Flexible Link Robot: Experimental Results
Modelación y Control de Posición del Extremo de un Robot de Eslabón Flexible: Resultados Experimentales
Juan Fernando Peza Solís*, Gerardo Silva Navarro** and Rafael Castro Linares***
Centro de Investigación y de Estudios Avanzados del I.P.N. Departamento de Ing. Eléctrica, Sección de Mecatrónica Av. Instituto Politécnico Nacional 2508. 07360 México D.F., México. E–mails: jpeza@cinvestav.mx*, gsilva@cinvestav.mx**, rcastro@cinvestav.mx***.
]]> Article received on March 10, 2008
Abstract
This work describes the modeling and control of an experimental platform associated to a single link flexible robot, whose motion is restricted to an horizontal plane, thus neglecting the gravity effects. The modeling problem is addressed using the so–called Euler–Bernoulli beam equation. The design, construction and integration of an experimental set–up developed for this work is also presented. Two main control schemes are then devised for controlling the end tip position of the flexible link, the passive velocity feedback and strain feedback approaches. Finally, the overall system performance is illustrated by some experimental results obtained with both control methods.
Keywords: Flexible link, Modal coordinates, Passivity based control, Strain feedback.
Resumen
En este trabajo se describe la modelación y control de una plataforma experimental de un robot con un eslabón flexible, cuyo movimiento se restringe a un plano horizontal. El eslabón flexible es una viga larga de acero con poco espesor, por lo que su ecuación de movimiento se obtiene a partir de la ecuación de Euler–Bernoulli, que describe a un sistema con masa y rigidez distribuida a lo largo de su coordenada espacial (longitud). Se describe el diseño, construcción e integración de la plataforma experimental. Para los propósitos de control de la posición del extremo libre se aplican dos esquemas de control, el enfoque basado en la retroalimentación pasiva de la velocidad y otro enfoque reciente conocido como retroalimentación del esfuerzo. Finalmente, el desempeño dinámico del sistema en lazo cerrado se ilustra mediante algunos resultados experimentales.
Palabras clave: Control basado en pasividad, Eslabón flexible, Coordenadas modales, Retroalimentación de esfuerzo.
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