Configuration-based compliance control of kinematically redundant robot arm Part II: Experimental validation

U okviru ovog rada koji se sastoji iz dva dela, prikazuje se novi pristup upravljanja popustljivošću vrha robota, odnosno elastomehaničkom interakcijom vrha robota i njegovog okruženja, primenom kinematske redundanse umesto aktuacione. U prvom delu ovaj pristup je prikazan kroz koncipiranje metode upravljanja krutošću promenom konfiguracije - Configuration-based Stiffness Control (CSC), za slučaj kinetosatičke konzistentnosti, primenom projekcije gradijenta optimizacione funkcije koja minimizira Euklidovu normu nedijagonalnih elemenata matrice krutosti robota izražene u unutrašnjim koordinatama. U drugom delu predložena metoda upravljanja popustljivošću je testirana simulacionim eksperimentima, koristeći kao simulacionu platformu dva posebna slučaja najjednostavnijih kinematski redundantnih robotskih ruku: Slučaj 1 - eksperimenti sa jednodimenzionim radnim prostorom (m = 1) i minimalno mogućom redundansom, r = (n - m) = 1, i Slučaj 2 - eksperimenti sa jednodimenzionim radnim prostorom (m = 1) i minimalno mogućom hiperredundansom, r = 2 i r > m. U oba slučaja singulariteti i ograničenja u opsezima pokretljivosti zglobova nisu razmatrani.This two-part paper presents an approach to the control of robot endpoint compliance, i.e., elasto-mechanical interaction between a robot and its environment using kinematic redundancy instead of actuation redundancy. In Part I this approach is developed by proposing the Configuration-based Stiffness Control (CSC) method for kinetostatically consistent control of robot compliant behaviour, based on the gradient projection of the cost function which minimizes the norm of off-diagonal elements of the jointspace matrix. In Part II validity of the proposed compliance control method is tested by simulation experiments using as a simulation platform two specific cases of most simple kinematically redundant robot arms: Case 1 - experiments with onedimensional taskspace (m=1) and minimal possible redundancy, r = (n - m) = 1, and Case 2 - experiments with onedimensional taskspace (m=1) and minimal possible hyper-redundancy, r = 2 and r > m. In both cases the singularity and joint limits were not considered

Autonomous Grasping Using Novel Distance Estimator

This paper introduces a novel distance estimator using monocular vision for autonomous underwater grasping. The presented method is also applicable to topside grasping operations. The estimator is developed for robot manipulators with a monocular camera placed near the gripper. The fact that the camera is attached near the gripper makes it possible to design a method for capturing images from different positions, as the relative position change can be measured. The presented system can estimate relative distance to an object of unknown size with good precision. The manipulator applied in the presented work is the SeaArm-2, a fully electric underwater small modular manipulator. The manipulator is unique in its integrated monocular camera in the end-effector module, and its design facilitates the use of different end-effector tools. The camera is used for supervision, object detection, and tracking. The distance estimator was validated in a laboratory setting through autonomous grasping experiments. The manipulator was able to search for and find, estimate the relative distance of, grasp, and retrieve the relevant object in 12 out of 12 trials.publishedVersio

A Synthetic Algorithm for Tracking a Moving Object in a Multiple-Dynamic Obstacles Environment Based on Kinematically Planar Redundant Manipulators

This paper presents a synthetic algorithm for tracking a moving object in a multiple-dynamic obstacles environment based on kinematically planar manipulators. By observing the motions of the object and obstacles, Spline filter associated with polynomial fitting is utilized to predict their moving paths for a period of time in the future. Several feasible paths for the manipulator in Cartesian space can be planned according to the predicted moving paths and the defined feasibility criterion. The shortest one among these feasible paths is selected as the optimized path. Then the real-time path along the optimized path is planned for the manipulator to track the moving object in real-time. To improve the convergence rate of tracking, a virtual controller based on PD controller is designed to adaptively adjust the real-time path. In the process of tracking, the null space of inverse kinematic and the local rotation coordinate method (LRCM) are utilized for the arms and the end-effector to avoid obstacles, respectively. Finally, the moving object in a multiple-dynamic obstacles environment is thus tracked via real-time updating the joint angles of manipulator according to the iterative method. Simulation results show that the proposed algorithm is feasible to track a moving object in a multiple-dynamic obstacles environment

Sliding mode control for robust and smooth reference tracking in robot visual servoing

[EN] An approach based on sliding mode is proposed in this work for reference tracking in robot visual servoing. In particular, 2 sliding mode controls are obtained depending on whether joint accelerations or joint jerks are considered as the discontinuous control action. Both sliding mode controls are extensively compared in a 3D-simulated environment with their equivalent well-known continuous controls, which can be found in the literature, to highlight their similarities and differences. The main advantages of the proposed method are smoothness, robustness, and low computational cost. The applicability and robustness of the proposed approach are substantiated by experimental results using a conventional 6R industrial manipulator (KUKA KR 6 R900 sixx [AGILUS]) for positioning and tracking tasks.Spanish Government, Grant/Award Number: BES-2010-038486; Generalitat Valenciana, Grant/Award Number: BEST/2017/029 and APOSTD/2016/044Muñoz-Benavent, P.; Gracia, L.; Solanes, JE.; Esparza, A.; Tornero, J. (2018). Sliding mode control for robust and smooth reference tracking in robot visual servoing. International Journal of Robust and Nonlinear Control. 28(5):1728-1756. https://doi.org/10.1002/rnc.3981S17281756285Hutchinson, S., Hager, G. D., & Corke, P. I. (1996). A tutorial on visual servo control. IEEE Transactions on Robotics and Automation, 12(5), 651-670. doi:10.1109/70.538972Chaumette, F., & Hutchinson, S. (2008). Visual Servoing and Visual Tracking. Springer Handbook of Robotics, 563-583. doi:10.1007/978-3-540-30301-5_25Corke, P. (2011). Robotics, Vision and Control. 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On improving robot image-based visual servoing based on dual-rate reference filtering control strategy. Robotica, 34(12), 2842-2859. doi:10.1017/s0263574715000454Elena M Cristiano M Damiano F Bonfe M Variable structure PID controller for cooperative eye-in-hand/eye-to-hand visual servoing 2003 Istanbul, Turkey https://doi.org/10.1109/CCA.2003.1223145Hashimoto, K., Ebine, T., & Kimura, H. (1996). Visual servoing with hand-eye manipulator-optimal control approach. IEEE Transactions on Robotics and Automation, 12(5), 766-774. doi:10.1109/70.538981Chan A Leonard S Croft EA Little JJ Collision-free visual servoing of an eye-in-hand manipulator via constraint-aware planning and control 2011 San Francisco, CA, USA https://doi.org/10.1109/ACC.2011.5991008Allibert, G., Courtial, E., & Chaumette, F. (2010). Visual Servoing via Nonlinear Predictive Control. Lecture Notes in Control and Information Sciences, 375-393. doi:10.1007/978-1-84996-089-2_20Kragic, D., & Christensen, H. I. (2003). Robust Visual Servoing. The International Journal of Robotics Research, 22(10-11), 923-939. doi:10.1177/027836490302210009Mezouar Y Chaumette F Path planning in image space for robust visual servoing 2000 San Francisco, CA, USA https://doi.org/10.1109/ROBOT.2000.846445Morel, G., Zanne, P., & Plestan, F. (2005). Robust visual servoing: bounding the task function tracking errors. IEEE Transactions on Control Systems Technology, 13(6), 998-1009. doi:10.1109/tcst.2005.857409Hammouda, L., Kaaniche, K., Mekki, H., & Chtourou, M. (2015). Robust visual servoing using global features based on random process. International Journal of Computational Vision and Robotics, 5(2), 138. doi:10.1504/ijcvr.2015.068803Yang YX Liu D Liu H Robot-self-learning visual servoing algorithm using neural networks 2002 Beijing, China https://doi.org/10.1109/ICMLC.2002.1174473Sadeghzadeh, M., Calvert, D., & Abdullah, H. A. (2014). Self-Learning Visual Servoing of Robot Manipulator Using Explanation-Based Fuzzy Neural Networks and Q-Learning. Journal of Intelligent & Robotic Systems, 78(1), 83-104. doi:10.1007/s10846-014-0151-5Lee AX Levine S Abbeel P Learning Visual Servoing With Deep Features and Fitted Q-Iteration 2017Fakhry, H. H., & Wilson, W. J. (1996). A modified resolved acceleration controller for position-based visual servoing. Mathematical and Computer Modelling, 24(5-6), 1-9. doi:10.1016/0895-7177(96)00112-4Keshmiri, M., Wen-Fang Xie, & Mohebbi, A. (2014). Augmented Image-Based Visual Servoing of a Manipulator Using Acceleration Command. IEEE Transactions on Industrial Electronics, 61(10), 5444-5452. doi:10.1109/tie.2014.2300048Edwards, C., & Spurgeon, S. (1998). Sliding Mode Control. doi:10.1201/9781498701822Zanne P Morel G Piestan F Robust vision based 3D trajectory tracking using sliding mode control 2000 San Francisco, CA, USAOliveira TR Peixoto AJ Leite AC Hsu L Sliding mode control of uncertain multivariable nonlinear systems applied to uncalibrated robotics visual servoing 2009 St. Louis, MO, USAOliveira, T. R., Leite, A. C., Peixoto, A. J., & Hsu, L. (2014). Overcoming Limitations of Uncalibrated Robotics Visual Servoing by means of Sliding Mode Control and Switching Monitoring Scheme. Asian Journal of Control, 16(3), 752-764. doi:10.1002/asjc.899Li, F., & Xie, H.-L. (2010). Sliding mode variable structure control for visual servoing system. International Journal of Automation and Computing, 7(3), 317-323. doi:10.1007/s11633-010-0509-5Kim J Kim D Choi S Won S Image-based visual servoing using sliding mode control 2006 Busan, South KoreaBurger W Dean-Leon E Cheng G Robust second order sliding mode control for 6D position based visual servoing with a redundant mobile manipulator 2015 Seoul, South KoreaBecerra, H. M., López-Nicolás, G., & Sagüés, C. (2011). A Sliding-Mode-Control Law for Mobile Robots Based on Epipolar Visual Servoing From Three Views. IEEE Transactions on Robotics, 27(1), 175-183. doi:10.1109/tro.2010.2091750Parsapour, M., & Taghirad, H. D. (2015). Kernel-based sliding mode control for visual servoing system. IET Computer Vision, 9(3), 309-320. doi:10.1049/iet-cvi.2013.0310Xin J Ran BJ Ma XM Robot visual sliding mode servoing using SIFT features 2016 Chengdu, ChinaZhao, Y. M., Lin, Y., Xi, F., Guo, S., & Ouyang, P. (2016). Switch-Based Sliding Mode Control for Position-Based Visual Servoing of Robotic Riveting System. Journal of Manufacturing Science and Engineering, 139(4). doi:10.1115/1.4034681Moosavian, S. A. A., & Papadopoulos, E. (2007). Modified transpose Jacobian control of robotic systems. Automatica, 43(7), 1226-1233. doi:10.1016/j.automatica.2006.12.029Sagara, S., & Taira, Y. (2008). Digital control of space robot manipulators with velocity type joint controller using transpose of generalized Jacobian matrix. Artificial Life and Robotics, 13(1), 355-358. doi:10.1007/s10015-008-0584-7Khalaji, A. K., & Moosavian, S. A. A. (2015). Modified transpose Jacobian control of a tractor-trailer wheeled robot. Journal of Mechanical Science and Technology, 29(9), 3961-3969. doi:10.1007/s12206-015-0841-3Utkin, V., Guldner, J., & Shi, J. (2017). Sliding Mode Control in Electro-Mechanical Systems. doi:10.1201/9781420065619Utkin, V. (2016). Discussion Aspects of High-Order Sliding Mode Control. IEEE Transactions on Automatic Control, 61(3), 829-833. doi:10.1109/tac.2015.2450571Romdhane, H., Dehri, K., & Nouri, A. S. (2016). Discrete second-order sliding mode control based on optimal sliding function vector for multivariable systems with input-output representation. International Journal of Robust and Nonlinear Control, 26(17), 3806-3830. doi:10.1002/rnc.3536Sharma, N. K., & Janardhanan, S. (2017). Optimal discrete higher-order sliding mode control of uncertain LTI systems with partial state information. International Journal of Robust and Nonlinear Control. doi:10.1002/rnc.3785LEVANT, A. (1993). Sliding order and sliding accuracy in sliding mode control. International Journal of Control, 58(6), 1247-1263. doi:10.1080/00207179308923053Levant, A. (2003). Higher-order sliding modes, differentiation and output-feedback control. International Journal of Control, 76(9-10), 924-941. doi:10.1080/0020717031000099029Bartolini, G., Ferrara, A., & Usai, E. (1998). Chattering avoidance by second-order sliding mode control. IEEE Transactions on Automatic Control, 43(2), 241-246. doi:10.1109/9.661074Siciliano, B., Sciavicco, L., Villani, L., & Oriolo, G. (2009). Robotics. Advanced Textbooks in Control and Signal Processing. doi:10.1007/978-1-84628-642-1Deo, A. S., & Walker, I. D. (1995). Overview of damped least-squares methods for inverse kinematics of robot manipulators. Journal of Intelligent & Robotic Systems, 14(1), 43-68. doi:10.1007/bf01254007WHEELER, G., SU, C.-Y., & STEPANENKO, Y. (1998). A Sliding Mode Controller with Improved Adaptation Laws for the Upper Bounds on the Norm of Uncertainties. Automatica, 34(12), 1657-1661. doi:10.1016/s0005-1098(98)80024-1Yu-Sheng Lu. (2009). Sliding-Mode Disturbance Observer With Switching-Gain Adaptation and Its Application to Optical Disk Drives. IEEE Transactions on Industrial Electronics, 56(9), 3743-3750. doi:10.1109/tie.2009.2025719Chen, X., Shen, W., Cao, Z., & Kapoor, A. (2014). A novel approach for state of charge estimation based on adaptive switching gain sliding mode observer in electric vehicles. Journal of Power Sources, 246, 667-678. doi:10.1016/j.jpowsour.2013.08.039Cong, B. L., Chen, Z., & Liu, X. D. (2012). On adaptive sliding mode control without switching gain overestimation. International Journal of Robust and Nonlinear Control, 24(3), 515-531. doi:10.1002/rnc.2902Taleb, M., Plestan, F., & Bououlid, B. (2014). An adaptive solution for robust control based on integral high-order sliding mode concept. International Journal of Robust and Nonlinear Control, 25(8), 1201-1213. doi:10.1002/rnc.3135Zhu, J., & Khayati, K. (2016). On a new adaptive sliding mode control for MIMO nonlinear systems with uncertainties of unknown bounds. International Journal of Robust and Nonlinear Control, 27(6), 942-962. doi:10.1002/rnc.3608Hafez AHA Cervera E Jawahar CV Hybrid visual servoing by boosting IBVS and PBVS 2008 Damascus, SyriaKermorgant O Chaumette F Combining IBVS and PBVS to ensure the visibility constraint 2011 San Francisco, CA, USACorke, P. I., & Hutchinson, S. A. (2001). A new partitioned approach to image-based visual servo control. IEEE Transactions on Robotics and Automation, 17(4), 507-515. doi:10.1109/70.954764Yang, Z., & Shen, S. (2017). Monocular Visual–Inertial State Estimation With Online Initialization and Camera–IMU Extrinsic Calibration. IEEE Transactions on Automation Science and Engineering, 14(1), 39-51. doi:10.1109/tase.2016.2550621Chesi G Hashimoto K Static-eye against hand-eye visual servoing 2002 Las Vegas, NV, USABourdis N Marraud D Sahbi H Camera pose estimation using visual servoing for aerial video change detection 2012 Munich, GermanyShademan A Janabi-Sharifi F Sensitivity analysis of EKF and iterated EKF pose estimation for position-based visual servoing 2005 USAMalis, E., Mezouar, Y., & Rives, P. (2010). Robustness of Image-Based Visual Servoing With a Calibrated Camera in the Presence of Uncertainties in the Three-Dimensional Structure. IEEE Transactions on Robotics, 26(1), 112-120. doi:10.1109/tro.2009.2033332Chen J Behal A Dawson D Dixon W Adaptive visual servoing in the presence of intrinsic calibration uncertainty 2003 USAMezouar Y Malis E Robustness of central catadioptric image-based visual servoing to uncertainties on 3D parameters 2004 Sendai, JapanMarchand, E., Spindler, F., & Chaumette, F. (2005). ViSP for visual servoing: a generic software platform with a wide class of robot control skills. IEEE Robotics & Automation Magazine, 12(4), 40-52. doi:10.1109/mra.2005.157702

Distributed framework for a multi-purpose household robotic arm

Projecte final de carrera fet en col.laboració amb l'Institut de Robòtica i Informàtica IndustrialThe concept of household robotic servants has been in our mind for ages, and domestic appliances are far more robotised than they used to be. At present, manufacturers are starting to introduce small, household human-interactive robots to the market. Any human-interactive device has safety, endurability and simplicity constraints, which are especially strict when it comes to robots. Indeed, we are still far from a multi-purpose intelligent household robot, but human-interactive robots and arti cial intelligence research has evolved considerably, demonstration prototypes are a proof of what can be done. This project contributes to the research in humaninteractive robots, as the robotic arm and hand used are specially designed for human-interactive applications. The present study provides a distributed framework for an arm and a hand devices based on the robotics YARP protocol using the WAMTM arm and the BarrettHandTM as well as a basic modular client application complemented with vision. Firstly, two device drivers and a network interface are designed and implemented to control the WAMTM arm and the BarrettHandTM from the network. The drivers allow abstract access to each device, providing three ports: command requests port, state requests port and asynchronous replies port. Secondly, each driver is then encapsulated by YARP devices publishing realtime monitoring feedback and motion control to the network through what is called a Network wrapper. In particular, the network wrapper for the WAMTM arm and BarrettHandTM provides a state port, command port, Remote Procedure Call (RPC) port and an asynchronous noti cations port. The state port provides the WAMTM position and orientation feedback at 50 Hz, which represents a maximum blindness of one centimetre. This rst part of the project sets the foundations of a distributed, complete robot, whose design enables processing and power payload to be shared by di erent workstations. Moreover, users are able to work with the robot remotely over Ethernet and Wireless through a clear, understandable local interface within YARP. In addition to the distributed robotic framework provided, a client software framework with vision is also supplied. The client framework establishes a general software shell for further development and is organized in the basic, separate robotic branches: control, vision and plani cation. The vision module supports distributed image grabbing on mobile robotics, and shared-memory for xed, local vision. In order to incorporate environment interaction and robot autonomy with the planner, hand-eye transformation matrices have been obtained to perform object grasping and manipulation. The image processing is based on OpenCV libraries and provides object recognition with Scale Invariant Feature Transform (SIFT) features matching, Hough transform and polygon approximation algorithms. Grasping and path planning use pre-de ned grasps which take into account the size, shape and orientation of the target objects. The proof-of-concept applications feature a household robotic arm with the ability to tidy randomly distributed common kitchen objects to speci ed locations, with robot real-time monitoring and basic control. The device modularity introduced in this project philosophy of decoupling communication, device local access and the components, was successful. Thanks to the abstract access and decoupling, the demonstration applications provided were easily deployed to test the arm's performance and its remote control and monitorization. Moreover, both resultant frameworks are arm-independent and the design is currently being adopted by other projects' devices within the IRI

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

Industrial human-robot collaboration: maximizing performance while maintaining safety

The goal of this thesis is to maximize performance in collaborative applications, while maintaining safety. For this, assembly workplaces are analyzed, typical tasks identified, and the potential of collaborative robots is elaborated. Current safety regulations are analyzed in order to identify the challenges in safe human-robot collaboration. Different methods are proposed to solve inefficiency in collaborative applications, in particular, intuitive programming of collaborative robots, efficient control with human-in-the-loop constraints, and a hardware solution, the Robotic Airbag.Das Ziel dieser Arbeit ist die Steigerung der Effizienz in kollaborativen Anwendungen, bei gleichzeitiger Einhaltung der Sicherheitsbestimmungen. Dazu werden Montagearbeitsplätze analysiert und das Potenzial kollaborativer Roboter erarbeitet. Aktuelle Sicherheitsvorschriften werden analysiert, um die Herausforderungen einer sicheren Mensch-Roboter-Zusammenarbeit zu identifizieren. Verschiedene Methoden wie intuitive Programmierung von kollaborativen Robotern, eine effiziente Steuerung mit Human-in-the-Loop Beschränkungen und eine Hardwarelösung - der Robotic Airbag - werden präsentiert

A Platform for Robot-Assisted Intracardiac Catheter Navigation

Steerable catheters are routinely deployed in the treatment of cardiac arrhythmias. During invasive electrophysiology studies, the catheter handle is manipulated by an interventionalist to guide the catheter's distal section toward endocardium for pacing and ablation. Catheter manipulation requires dexterity and experience, and exposes the interventionalist to ionizing radiation. Through the course of this research, a platform was developed to assist and enhance the navigation of the catheter inside the cardiac chambers. This robotic platform replaces the interventionalist's hand in catheter manipulation and provides the option to force the catheter tip in arbitrary directions using a 3D input device or to automatically navigate the catheter to desired positions within a cardiac chamber by commanding the software to do so. To accomplish catheter navigation, the catheter was modeled as a continuum manipulator, and utilizing robot kinematics, catheter tip position control was designed and implemented. An electromagnetic tracking system was utilized to measure the position and orientation of two key points in catheter model, for position feedback to the control system. A software platform was developed to implement the navigation and control strategies and to interface with the robot, the 3D input device and the tracking system. The catheter modeling was validated through in-vitro experiments with a static phantom, and in-vivo experiments on three live swines. The feasibility of automatic navigation was also veri ed by navigating to three landmarks in the beating heart of swine subjects, and comparing their performance with that of an experienced interventionalist using quasi biplane fluoroscopy. The platform realizes automatic, assisted, and motorized navigation under the interventionalist's control, thus reducing the dependence of successful navigation on the dexterity and manipulation skills of the interventionalist, and providing a means to reduce the exposure to X-ray radiation. Upon further development, the platform could be adopted for human deployment

A contribution to the development of assistance systems for serial and parallel robots using the example of mobile concrete pumps and tendon-based rack feeders

Der zunehmende Kostendruck in der Industrie zwingt die Unternehmen, jegliche Art von Prozessen, sei es beispielsweise der Herstellungsprozess eines Produkts oder ein logistischer Lagerverwaltungs-Prozess, effizient zu gestalten. Ein Potential zur Effizienzsteigerung bildet die Prozessautomatisierung. Grenzen der Automatisierung entstehen bei Arbeitsabläufen, die eine gewisse Flexibilität erfordern, wie beispielsweise bei einem Prozess in einer sich ständig ändernden Umgebung mit Personen oder anderen bewegten Hindernissen. Ist ein Prozess vollautomatisiert aufgrund des hohen technischen Aufwands auch wirtschaftlich nicht realisierbar, bieten Assistenzsysteme zumindest die Möglichkeit, Arbeitsabläufe zu optimieren, wobei dem Assistenzsystem, in der Regel also der Maschine, nicht die volle Verantwortung über den Prozessablauf übertragen wird. In diesem Beitrag wird auf Basis eines quadratischen Optimierungsproblems ein echtzeitfähiger Algorithmus entwickelt, mit dem es möglich ist, die inverse Kinematik kinematisch redundanter Manipulatoren und die minimale Seilkraftverteilung seilbasierter Stewart-Gough-Plattformen zu lösen. Diese Lösung bildet die Grundlage für modellbasierte Regelungskonzepte, womit voll- bzw. teilautomatierte Prozesse (Assistenzsysteme) serieller und paralleler Roboter realisiert werden können. Der in diesem Beitrag entwickelte Algorithmus wird auf zwei Beispiele aus dem Bereich der Robotik angewendet: die Autobetonpumpe als ein Beispiel serieller, kinematisch redundanter Manipulatoren und das seilbasierte Regalbediengerät als ein Beispiel für parallele Seilroboter auf Basis der Stewart-Gough-Plattform.The increasing cost pressure in the industry forces the companies to design any kind of process in an efficient manner, for instance the manufacturing process of a product or a logistical warehouse management process. An increase in efficiency can be established by a process automation.However, limitations of automation arise in operations which require a certain flexibility such as a process in a permanently changing environment with persons and other moving obstacles. Once a fully automated process cannot be realised due to its technical complexity and lack of profitability, at least assistance systems can offer the potential to optimize the work flow, whereby the assistance system, so usually the machine, does not bear the full responsibility. In this contribution a real-time capable algorithm is developed based on the quadratic optimization problem which enables the calculation of the inverse kinematics of kinematically redundant manipulators, and of optimal tendon force distributions of tendon-based Stewart-Gough platforms. This solution constitutes the basis for model-based control concepts in order to realise fully and semi-automatic processes (assistance systems) of serial and parallel robots. The algorithm developed in this contribution is applied on two examples from the field of robotics: the mobile concrete pump as an example of a serial, kinematically redundant manipulator, and the tendon-based rack feeder system as an example of a parallel tendon robot based on the Stewart-Gough platform

Postprocesamiento CAM-ROBOTICA orientado al prototipado y mecanizado en células robotizadas complejas

The main interest of this thesis consists of the study and implementation of postprocessors to adapt the toolpath generated by a Computer Aided Manufacturing (CAM) system to a complex robotic workcell of eight joints, devoted to the rapid prototyping of 3D CAD-defined products. It consists of a 6R industrial manipulator mounted on a linear track and synchronized with a rotary table. To accomplish this main objective, previous work is required. Each task carried out entails a methodology, objective and partial results that complement each other, namely: - It is described the architecture of the workcell in depth, at both displacement and joint-rate levels, for both direct and inverse resolutions. The conditioning of the Jacobian matrix is described as kinetostatic performance index to evaluate the vicinity to singular postures. These ones are analysed from a geometric point of view. - Prior to any machining, the additional external joints require a calibration done in situ, usually in an industrial environment. A novel Non-contact Planar Constraint Calibration method is developed to estimate the external joints configuration parameters by means of a laser displacement sensor. - A first control is originally done by means of a fuzzy inference engine at the displacement level, which is integrated within the postprocessor of the CAM software. - Several Redundancy Resolution Schemes (RRS) at the joint-rate level are compared for the configuration of the postprocessor, dealing not only with the additional joints (intrinsic redundancy) but also with the redundancy due to the symmetry on the milling tool (functional redundancy). - The use of these schemes is optimized by adjusting two performance criterion vectors related to both singularity avoidance and maintenance of a preferred reference posture, as secondary tasks to be done during the path tracking. Two innovative fuzzy inference engines actively adjust the weight of each joint in these tasks.Andrés De La Esperanza, FJ. (2011). Postprocesamiento CAM-ROBOTICA orientado al prototipado y mecanizado en células robotizadas complejas [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/10627Palanci