A supervisory loop approach to fulfill workspace constraints in redundant robots

An approach based on geometric invariance and sliding mode ideas is proposed for redundancy resolution in robotic systems to fulfill configuration and workspace constraints caused by robot mechanical limits, collision avoidance, industrial security, etc. Some interesting features of the proposal are that: (1) it can be interpreted as a limit case of the classical potential field-based approach for collision avoidance which requires using variable structure control concepts, (2) it allows reaching the limit surface of the constraints smoothly, depending on a free design parameter, and (3) it can be easily added as a supervisory block to pre-existing redundancy resolution schemes. The algorithm is evaluated in simulation on a 6R planar robot and on the freely accessible 6R robot model PUMA-560, for which the main features of the method are illustrated.This research is partially supported by DISICOM project PROM-ETEO 2008/088 of Generalitat Valenciana (Spain), research project DPI2011-27845-C02-01 of the Spanish Government (Spain), Technical University of Valencia (Spain), and the Argentinian Government (UNLP 11I127, CONICET PIP 112-200801-0, ANPCyT PICT 2007 00535).Gracia Calandin, LI.; Sala, A.; Garelli, F. (2012). A supervisory loop approach to fulfill workspace constraints in redundant robots. Robotics and Autonomous Systems. 60(1):1-15. https://doi.org/10.1016/j.robot.2011.07.008S11560

A supervisory loop approach to fulfill workspace constraints in redundant robots

An approach based on geometric invariance and sliding mode ideas is proposed for redundancy resolution in robotic systems to fulfill configuration and workspace constraints caused by robot mechanical limits, collision avoidance, industrial security, etc. Some interesting features of the proposal are that: (1) it can be interpreted as a limit case of the classical potential field-based approach for collision avoidance which requires using variable structure control concepts, (2) it allows reaching the limit surface of the constraints smoothly, depending on a free design parameter, and (3) it can be easily added as a supervisory block to pre-existing redundancy resolution schemes. The algorithm is evaluated in simulation on a 6R planar robot and on the freely accessible 6R robot model PUMA-560, for which the main features of the method are illustrated.Facultad de Ingenierí

Sliding mode reference coordination of constrained feedback systems

This paper addresses the problem of coordinating dynamical systems with possibly different dynamics (e.g., linear and nonlinear, different orders, constraints, etc.) to achieve some desired collective behavior under the constraints and capabilities of each system. To this end, we develop a new methodology based on reference conditioning techniques using geometric set invariance and sliding mode control: the sliding mode reference coordination (SMRCoord). The main idea is to coordinate the systems references. Starting from a general framework, we propose two approaches: a local one through direct interactions between the different systems by sharing and conditioning their own references and a global centralized one, where a central node makes decisions using information coming from the systems references. In particular, in this work we focus in implementation on multivariable systems like unmanned aerial vehicles (UAVs) and robustness to external perturbations. To show the applicability of the approach, the problem of coordinating UAVs with input constraints is addressed as a particular case of multivariable reference coordination with both global and local configuration.Facultad de Ingenierí

Reactive Sliding-Mode Algorithm for Collision Avoidance in Robotic Systems

© 2013 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.” Upon publication, authors are asked to include either a link to the abstract of the published article in IEEE Xplore®, or the article’s Digital Object Identifier (DOI).This brief presents a reactive reference conditioning algorithm for robot collision avoidance based on geometric invariance and sliding-mode (SM) ideas. First, constraints are defined in terms of the measurements given by the robot s sensors in order to guarantee that collisions will not occur. Then, a supervisory loop ensures the fulfillment of the constraints modifying the reference trajectory as much as necessary by means of a discontinuous control law. The proposed algorithm activates only when the constraints are about to be violated and, thus, in contrast to conventional SM approaches, there exists no reaching mode to the limit surface of the constraints (sliding surface). The validity and effectiveness of the proposed approach is substantiated by simulation and experimental results using a mobile robot equipped with infrared sensors.This work was supported in part by research under Project DPI2011-27845-C02-01 (Spanish Government), Projects PAID-05-11-2640, and PAID-00-12-SP20120159, (Universitat Politecnica de Valencia, Spain), and Projects ANPCyT PICT-2011-0888, CONICET PIP 112-2011-00361, and UNLP I164 in Argentina. Recommended by Associate Editor M. Zefran.Gracia Calandin, LI.; Garelli, F.; Sala, A. (2013). Reactive Sliding-Mode Algorithm for Collision Avoidance in Robotic Systems. IEEE Transactions on Control Systems Technology. 21(6):2391-2399. https://doi.org/10.1109/TCST.2012.2231866S2391239921

Sliding mode reference coordination of constrained feedback systems

This paper addresses the problem of coordinating dynamical systems with possibly different dynamics (e.g., linear and nonlinear, different orders, constraints, etc.) to achieve some desired collective behavior under the constraints and capabilities of each system. To this end, we develop a new methodology based on reference conditioning techniques using geometric set invariance and sliding mode control: the sliding mode reference coordination (SMRCoord). The main idea is to coordinate the systems references. Starting from a general framework, we propose two approaches: a local one through direct interactions between the different systems by sharing and conditioning their own references and a global centralized one, where a central node makes decisions using information coming from the systems references. In particular, in this work we focus in implementation on multivariable systems like unmanned aerial vehicles (UAVs) and robustness to external perturbations. To show the applicability of the approach, the problem of coordinating UAVs with input constraints is addressed as a particular case of multivariable reference coordination with both global and local configuration.Facultad de Ingenierí

Sliding Mode Reference Coordination of Constrained Feedback Systems

[EN] This paper addresses the problem of coordinating dynamical systems with possibly different dynamics (e.g., linear and nonlinear, different orders, constraints, etc.) to achieve some desired collective behavior under the constraints and capabilities of each system. To this end, we develop a new methodology based on reference conditioning techniques using geometric set invariance and sliding mode control: the sliding mode reference coordination (SMRCoord). The main idea is to coordinate the systems references. Starting from a general framework, we propose two approaches: a local one through direct interactions between the different systems by sharing and conditioning their own references and a global centralized one, where a central node makes decisions using information coming from the systems references. In particular, in this work we focus in implementation on multivariable systems like unmanned aerial vehicles (UAVs) and robustness to external perturbations. To show the applicability of the approach, the problem of coordinating UAVs with input constraints is addressed as a particular case of multivariable reference coordination with both global and local configuration.Research in this area is partially supported by Argentine government (ANPCyT PICT 2011-0888 and CONICET PIP 112-2011-00361), Spanish government (FEDER-CICYT DPI2011-28112-C04-01), and Universitat Politecnica de Valencia (Grant FPI/2009-21)Vignoni, A.; Garelli, F.; Picó, J. (2013). Sliding Mode Reference Coordination of Constrained Feedback Systems. Mathematical Problems in Engineering. 2013:1-11. https://doi.org/10.1155/2013/764348S1112013Information consensus in multivehicle cooperative control. (2007). IEEE Control Systems, 27(2), 71-82. doi:10.1109/mcs.2007.338264Cao, Y., Yu, W., Ren, W., & Chen, G. (2013). An Overview of Recent Progress in the Study of Distributed Multi-Agent Coordination. 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Design of a polishing tool for collaborative robotics using minimum viable product approach

This is an Author's Accepted Manuscript of an article published in Carlos Perez-Vidal, Luis Gracia, Samuel Sanchez-Caballero, J. Ernesto Solanes, Alessandro Saccon & Josep Tornero (2019) Design of a polishing tool for collaborative robotics using minimum viable product approach, International Journal of Computer Integrated Manufacturing, 32:9, 848-857, DOI: 10.1080/0951192X.2019.1637026 [copyright Taylor & Francis], available online at: http://www.tandfonline.com/10.1080/0951192X.2019.1637026[EN] A collaborative tool for robotic polishing is developed in this work in order to allow the simultaneous operation of the robot system and human operator to cooperatively carry out the polishing task. For this purpose, the collaborative environment is detailed and the polishing application is designed. Moreover, the polishing tool is developed and its implementation using the minimum viable product approach is obtained. Furthermore, a robust hybrid position-force control is proposed to use the developed tool attached to a robot system and some experiments are given to show its performance.This work was supported in part by the Ministerio de Ciencia e Innovacion (Spanish Government) under project [DPI2017-87656-C2-1-R] and the Generalitat Valenciana under Grant [VALi+ d APOSTD/2016/044].Perez-Vidal, C.; Gracia Calandin, LI.; Sanchez-Caballero, S.; Solanes Galbis, JE.; Saccon, A.; Tornero Montserrat, J. (2019). Design of a polishing tool for collaborative robotics using minimum viable product approach. International Journal of Computer Integrated Manufacturing. 32(9):848-857. https://doi.org/10.1080/0951192X.2019.1637026S848857329Alders, K., M. Lehe, and G. Wan. 2001. “Method for the Automatic Recognition of Surface Defects in Body Shells and Device for Carrying Out Said Method” US Patent 6,320,654, Accessed 2001 November. https://www.google.ch/patents/US6320654Alexopoulos, K., Mavrikios, D., & Chryssolouris, G. (2013). ErgoToolkit: an ergonomic analysis tool in a virtual manufacturing environment. International Journal of Computer Integrated Manufacturing, 26(5), 440-452. doi:10.1080/0951192x.2012.731610Andres, J., Gracia, L., & Tornero, J. (2011). Calibration and control of a redundant robotic workcell for milling tasks. International Journal of Computer Integrated Manufacturing, 24(6), 561-573. doi:10.1080/0951192x.2011.566284Arnal, L., Solanes, J. E., Molina, J., & Tornero, J. (2017). Detecting dings and dents on specular car body surfaces based on optical flow. Journal of Manufacturing Systems, 45, 306-321. doi:10.1016/j.jmsy.2017.07.006Blank, S. 2010. “Perfection By Subtraction - The Minimum Feature Set”. Accessed 2018 August. http://steveblank.com/2010/03/04/perfection-by-subtraction-the-minimum-feature-set/Dimeas, F., & Aspragathos, N. (2016). Online Stability in Human-Robot Cooperation with Admittance Control. IEEE Transactions on Haptics, 9(2), 267-278. doi:10.1109/toh.2016.2518670Fitzgerald, C. “Developing Baxter, A new industrial robot with common sense for U.S. manufacturing.” 2013.Gracia, L., Sala, A., & Garelli, F. (2012). A supervisory loop approach to fulfill workspace constraints in redundant robots. Robotics and Autonomous Systems, 60(1), 1-15. doi:10.1016/j.robot.2011.07.008Gracia, L., Sala, A., & Garelli, F. (2014). Robot coordination using task-priority and sliding-mode techniques. Robotics and Computer-Integrated Manufacturing, 30(1), 74-89. doi:10.1016/j.rcim.2013.08.003Gracia, L., Solanes, J. E., Muñoz-Benavent, P., Valls Miro, J., Perez-Vidal, C., & Tornero, J. (2018). Adaptive Sliding Mode Control for Robotic Surface Treatment Using Force Feedback. Mechatronics, 52, 102-118. doi:10.1016/j.mechatronics.2018.04.008Julius, R., Schürenberg, M., Schumacher, F., & Fay, A. (2017). Transformation of GRAFCET to PLC code including hierarchical structures. Control Engineering Practice, 64, 173-194. doi:10.1016/j.conengprac.2017.03.012. E. K. (2016). TOWARDS AN AUTOMATED POLISHING SYSTEM - CAPTURING MANUAL POLISHING OPERATIONS. International Journal of Research in Engineering and Technology, 05(07), 182-192. doi:10.15623/ijret.2016.0507030Khan, A. M., Yun, D., Zuhaib, K. M., Iqbal, J., Yan, R.-J., Khan, F., & Han, C. (2017). Estimation of Desired Motion Intention and compliance control for upper limb assist exoskeleton. International Journal of Control, Automation and Systems, 15(2), 802-814. doi:10.1007/s12555-015-0151-7Kirschner, D., Velik, R., Yahyanejad, S., Brandstötter, M., & Hofbaur, M. (2016). YuMi, Come and Play with Me! A Collaborative Robot for Piecing Together a Tangram Puzzle. Interactive Collaborative Robotics, 243-251. doi:10.1007/978-3-319-43955-6_29Mohammad, A. E. K., Hong, J., & Wang, D. (2018). Design of a force-controlled end-effector with low-inertia effect for robotic polishing using macro-mini robot approach. Robotics and Computer-Integrated Manufacturing, 49, 54-65. doi:10.1016/j.rcim.2017.05.011Nagata, F., Hase, T., Haga, Z., Omoto, M., & Watanabe, K. (2007). CAD/CAM-based position/force controller for a mold polishing robot. Mechatronics, 17(4-5), 207-216. doi:10.1016/j.mechatronics.2007.01.003Nakamura, Y., Hanafusa, H., & Yoshikawa, T. (1987). Task-Priority Based Redundancy Control of Robot Manipulators. The International Journal of Robotics Research, 6(2), 3-15. doi:10.1177/027836498700600201Ries, E. 2009. “What is the Minimum Viable Product”. March. Accessed 2018 August. http://venturehacks.com/articles/minimum-viable-productRobinson, F. 2001 “A Proven Methodology to Maximize Return on Risk”. Accessed 2018 August. http://www.syncdev.com/minimum-viable-productShepherd, S., & Buchstab, A. (2014). KUKA Robots On-Site. Robotic Fabrication in Architecture, Art and Design 2014, 373-380. doi:10.1007/978-3-319-04663-1_26SYMPLEXITY. “Symbiotic Human-Robot Solutions for Complex Surface Finishing Operations.” European project funded by E.U. through the H2020. Project no. 637080. Call: H2020-FoF-2014. Topic: FoF-06-2014. Starting date: 01/ 01/2015.Duration: 48 months. Accessed 2019 March. https://www.symplexity.eu/Vihlborg, P., I. Bryngelsson, B. Lindgren, L. G. Gunnarsson, and P. Graff. 2017. “Associatio between vibration exposure and hand-arm vibration symptoms in a Swedish mechanical industry.” February 2017.Vogel, J., Haddadin, S., Jarosiewicz, B., Simeral, J. D., Bacher, D., Hochberg, L. R., … van der Smagt, P. (2015). An assistive decision-and-control architecture for force-sensitive hand–arm systems driven by human–machine interfaces. 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Robot Visual Servoing Using Discontinuous Control

This work presents different proposals to deal with common problems in robot visual servoing based on the application of discontinuous control methods. The feasibility and effectiveness of the proposed approaches are substantiated by simulation results and real experiments using a 6R industrial manipulator. The main contributions are: - Geometric invariance using sliding mode control (Chapter 3): the defined higher-order invariance is used by the proposed approaches to tackle problems in visual servoing. Proofs of invariance condition are presented. - Fulfillment of constraints in visual servoing (Chapter 4): the proposal uses sliding mode methods to satisfy mechanical and visual constraints in visual servoing, while a secondary task is considered to properly track the target object. The main advantages of the proposed approach are: low computational cost, robustness and fully utilization of the allowed space for the constraints. - Robust auto tool change for industrial robots using visual servoing (Chapter 4): visual servoing and the proposed method for constraints fulfillment are applied to an automated solution for tool changing in industrial robots. The robustness of the proposed method is due to the control law of the visual servoing, which uses the information acquired by the vision system to close a feedback control loop. Furthermore, sliding mode control is simultaneously used in a prioritized level to satisfy the aforementioned constraints. Thus, the global control accurately places the tool in the warehouse, but satisfying the robot constraints. - Sliding mode controller for reference tracking (Chapter 5): an approach based on sliding mode control is proposed for reference tracking in robot visual servoing using industrial robot manipulators. The novelty of the proposal is the introduction of a sliding mode controller that uses a high-order discontinuous control signal, i.e., joint accelerations or joint jerks, in order to obtain a smoother behavior and ensure the robot system stability, which is demonstrated with a theoretical proof. - PWM and PFM for visual servoing in fully decoupled approaches (Chapter 6): discontinuous control based on pulse width and pulse frequency modulation is proposed for fully decoupled position based visual servoing approaches, in order to get the same convergence time for camera translation and rotation. Moreover, other results obtained in visual servoing applications are also described.Este trabajo presenta diferentes propuestas para tratar problemas habituales en el control de robots por realimentación visual, basadas en la aplicación de métodos de control discontinuos. La viabilidad y eficacia de las propuestas se fundamenta con resultados en simulación y con experimentos reales utilizando un robot manipulador industrial 6R. Las principales contribuciones son: - Invariancia geométrica utilizando control en modo deslizante (Capítulo 3): la invariancia de alto orden definida aquí es utilizada después por los métodos propuestos, para tratar problemas en control por realimentación visual. Se apuertan pruebas teóricas de la condición de invariancia. - Cumplimiento de restricciones en control por realimentación visual (Capítulo 4): esta propuesta utiliza métodos de control en modo deslizante para satisfacer restricciones mecánicas y visuales en control por realimentación visual, mientras una tarea secundaria se encarga del seguimiento del objeto. Las principales ventajas de la propuesta son: bajo coste computacional, robustez y plena utilización del espacio disponible para las restricciones. - Cambio de herramienta robusto para un robot industrial mediante control por realimentación visual (Capítulo 4): el control por realimentación visual y el método propuesto para el cumplimiento de las restricciones se aplican a una solución automatizada para el cambio de herramienta en robots industriales. La robustez de la propuesta radica en el uso del control por realimentación visual, que utiliza información del sistema de visión para cerrar el lazo de control. Además, el control en modo deslizante se utiliza simultáneamente en un nivel de prioridad superior para satisfacer las restricciones. Así pues, el control es capaz de dejar la herramienta en el intercambiador de herramientas de forma precisa, a la par que satisface las restricciones del robot. - Controlador en modo deslizante para seguimiento de referencia (Capítulo 5): se propone un enfoque basado en el control en modo deslizante para seguimiento de referencia en robots manipuladores industriales controlados por realimentación visual. La novedad de la propuesta radica en la introducción de un controlador en modo deslizante que utiliza la señal de control discontinua de alto orden, i.e. aceleraciones o jerks de las articulaciones, para obtener un comportamiento más suave y asegurar la estabilidad del sistema robótico, lo que se demuestra con una prueba teórica. - Control por realimentación visual mediante PWM y PFM en métodos completamente desacoplados (Capítulo 6): se propone un control discontinuo basado en modulación del ancho y frecuencia del pulso para métodos completamente desacoplados de control por realimentación visual basados en posición, con el objetivo de conseguir el mismo tiempo de convergencia para los movimientos de rotación y traslación de la cámara . Además, se presentan también otros resultados obtenidos en aplicaciones de control por realimentación visual.Aquest treball presenta diferents propostes per a tractar problemes habituals en el control de robots per realimentació visual, basades en l'aplicació de mètodes de control discontinus. La viabilitat i eficàcia de les propostes es fonamenta amb resultats en simulació i amb experiments reals utilitzant un robot manipulador industrial 6R. Les principals contribucions són: - Invariància geomètrica utilitzant control en mode lliscant (Capítol 3): la invariància d'alt ordre definida ací és utilitzada després pels mètodes proposats, per a tractar problemes en control per realimentació visual. S'aporten proves teòriques de la condició d'invariància. - Compliment de restriccions en control per realimentació visual (Capítol 4): aquesta proposta utilitza mètodes de control en mode lliscant per a satisfer restriccions mecàniques i visuals en control per realimentació visual, mentre una tasca secundària s'encarrega del seguiment de l'objecte. Els principals avantatges de la proposta són: baix cost computacional, robustesa i plena utilització de l'espai disponible per a les restriccions. - Canvi de ferramenta robust per a un robot industrial mitjançant control per realimentació visual (Capítol 4): el control per realimentació visual i el mètode proposat per al compliment de les restriccions s'apliquen a una solució automatitzada per al canvi de ferramenta en robots industrials. La robustesa de la proposta radica en l'ús del control per realimentació visual, que utilitza informació del sistema de visió per a tancar el llaç de control. A més, el control en mode lliscant s'utilitza simultàniament en un nivell de prioritat superior per a satisfer les restriccions. Així doncs, el control és capaç de deixar la ferramenta en l'intercanviador de ferramentes de forma precisa, a la vegada que satisfà les restriccions del robot. - Controlador en mode lliscant per a seguiment de referència (Capítol 5): es proposa un enfocament basat en el control en mode lliscant per a seguiment de referència en robots manipuladors industrials controlats per realimentació visual. La novetat de la proposta radica en la introducció d'un controlador en mode lliscant que utilitza senyal de control discontínua d'alt ordre, i.e. acceleracions o jerks de les articulacions, per a obtindre un comportament més suau i assegurar l'estabilitat del sistema robòtic, la qual cosa es demostra amb una prova teòrica. - Control per realimentació visual mitjançant PWM i PFM en mètodes completament desacoblats (Capítol 6): es proposa un control discontinu basat en modulació de l'ample i la freqüència del pols per a mètodes completament desacoblats de control per realimentació visual basats en posició, amb l'objectiu d'aconseguir el mateix temps de convergència per als moviments de rotació i translació de la càmera. A més, es presenten també altres resultats obtinguts en aplicacions de control per realimentació visual.Muñoz Benavent, P. (2017). Robot Visual Servoing Using Discontinuous Control [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/90430TESI