Robust Pose Control of Robot Manipulators Using Conformal Geometric Algebra

A controller, based on sliding mode control, is proposed for the n-link robotic manipulator pose tracking problem. The point pair (a geometric entity expressed in geometric algebra) is used to represent position and orientation of the end-effector of a manipulator. This permits us to express the direct and differential kinematics of the endeffector of the manipulator in a simple and compact way. For the control, a sliding mode controller is designed with the following properties: robustness against perturbations and parameter variations, finite time convergence, and easy implementation. Finally, the application, of the proposed controller in a 6 DOF robotic manipulator is presented via simulation.Consejo Nacional de Ciencia y Tecnologí

Modeling, Analysis, Force Sensing and Control of Continuum Robots for Minimally Invasive Surgery

This dissertation describes design, modeling and application of continuum robotics for surgical applications, specifically parallel continuum robots (PCRs) and concentric tube manipulators (CTMs). The introduction of robotics into surgical applications has allowed for a greater degree of precision, less invasive access to more remote surgical sites, and user-intuitive interfaces with enhanced vision systems. The most recent developments have been in the space of continuum robots, whose exible structure create an inherent safety factor when in contact with fragile tissues. The design challenges that exist involve balancing size and strength of the manipulators, controlling the manipulators over long transmission pathways, and incorporating force sensing and feedback from the manipulators to the user. Contributions presented in this work include: (1) prototyping, design, force sensing, and force control investigations of PCRs, and (2) prototyping of a concentric tube manipulator for use in a standard colonoscope. A general kinetostatic model is presented for PCRs along with identification of multiple physical constraints encountered in design and construction. Design considerations and manipulator capabilities are examined in the form of matrix metrics and ellipsoid representations. Finally, force sensing and control are explored and experimental results are provided showing the accuracy of force estimates based on actuation force measurements and control capabilities. An overview of the design requirements, manipulator construction, analysis and experimental results are provided for a CTM used as a tool manipulator in a traditional colonoscope. Currently, tools used in colonoscopic procedures are straight and exit the front of the scope with 1 DOF of operation (jaws of a grasper, tightening of a loop, etc.). This research shows that with a CTM deployed, the dexterity of these tools can be increased dramatically, increasing accuracy of tool operation, ease of use and safety of the overall procedure. The prototype investigated in this work allows for multiple tools to be used during a single procedure. Experimental results show the feasibility and advantages of the newly-designed manipulators

Fractional multi-loop active disturbance rejection control for a lower knee exoskeleton system

Rehabilitation Exoskeleton is becoming more and more important in physiotherapists’ routine work. To improve the treatment performance, such as reducing the recovery period and/or monitoring and reacting to unpredictable situations, the rehabilitation manipulators need to help the patients in various physical trainings. A special case of the active disturbance rejection control (ADRC) is applied to govern a proper realisation of basic limb rehabilitation trainings. The experimental study is performed on a model of a flexible joint manipulator, whose behaviour resembles a real exoskeleton rehabilitation device (a one-degree-of-freedom, rigid-link, flexible-joint manipulator). The fractional (FADRC) is an unconventional model-independent approach, acknowledged as an effective controller in the existence of total plant uncertainties, and these uncertainties are inclusive of the total disturbances and unknown dynamics of the plant. In this work, three FADRC schemes are used, the first one using a fractional state observer (FSO), or FADRC1, second one using a fractional proportional-derivative controller (FPD), or FADRC2, and the third one a Multi-loop fractional in PD-loop controller and the observer-loop (Feedforward and Feedback), or FADRC3. The simulated Exoskeleton system is subjected to a noise disturbance and the FADRC3 shows the effectiveness to compensate all these effects and satisfies the desired position when compared with FADRC1 and FADRC2. The design and simulation were carried out in MATLAB/Simulink

Bimanual robot control for surface treatment tasks

This is an Author's Accepted Manuscript of an article published in Alberto García, J. Ernesto Solanes, Luis Gracia, Pau Muñoz-Benavent, Vicent Girbés-Juan & Josep Tornero (2022) Bimanual robot control for surface treatment tasks, International Journal of Systems Science, 53:1, 74-107, DOI: 10.1080/00207721.2021.1938279 [copyright Taylor & Francis], available online at: http://www.tandfonline.com/10.1080/00207721.2021.1938279[EN] This work develops a method to perform surface treatment tasks using a bimanual robotic system, i.e. two robot arms cooperatively performing the task. In particular, one robot arm holds the work-piece while the other robot arm has the treatment tool attached to its end-effector. Moreover, the human user teleoperates all the six coordinates of the former robot arm and two coordinates of the latter robot arm, i.e. the teleoperator can move the treatment tool on the plane given by the work- piece surface. Furthermore, a force sensor attached to the treatment tool is used to automatically attain the desired pressure between the tool and the workpiece and to automatically keep the tool orientation orthogonal to the workpiece surface. In addition, to assist the human user during the teleoperation, several constraints are defined for both robot arms in order to avoid exceeding the allowed workspace, e.g. to avoid collisions with other objects in the environment. The theory used in this work to develop the bimanual robot control relies on sliding mode control and task prioritisation. Finally, the feasibility and effectiveness of the method are shown through experimental results using two robot arms.This work was supported by Generalitat Valenciana [grant numbers ACIF/2019/007 and GV/2021/181] and Spanish Ministry of Science and Innovation [grant number PID2020117421RB-C21].García-Fernández, A.; Solanes, JE.; Gracia Calandin, LI.; Muñoz-Benavent, P.; Girbés-Juan, V.; Tornero, J. (2022). Bimanual robot control for surface treatment tasks. International Journal of Systems Science. 53(1):74-107. https://doi.org/10.1080/00207721.2021.19382797410753

Bimanual robot control for surface treatment tasks

This work develops a method to perform surface treatment tasks using a bimanual robotic system, i.e. two robot arms cooperatively performing the task. In particular, one robot arm holds the workpiece while the other robot arm has the treatment tool attached to its end-effector. Moreover, the human user teleoperates all the six coordinates of the former robot arm and two coordinates of the latter robot arm, i.e. the teleoperator can move the treatment tool on the plane given by the workpiece surface. Furthermore, a force sensor attached to the treatment tool is used to automatically attain the desired pressure between the tool and the workpiece and to automatically keep the tool orientation orthogonal to the workpiece surface. In addition, to assist the human user during the teleoperation, several constraints are defined for both robot arms in order to avoid exceeding the allowed workspace, e.g. to avoid collisions with other objects in the environment. The theory used in this work to develop the bimanual robot control relies on sliding mode control and task prioritisation. Finally, the feasibility and effectiveness of the method are shown through experimental results using two robot arms

Model-Free Control of an Unmanned Aircraft Quadcopter Type System

A model-free control algorithm based on the sliding mode control method for unmanned aircraft systems is proposed. The mathematical model of the dynamic system is not required to derive the sliding mode control law for this proposed method. The knowledge of the system’s order, state measurements and control input gain matrix shape and bounds are assumed to derive the control law to track the required trajectories. Lyapunov’s Stability criteria is used to ensure closed-loop asymptotic stability and the error estimate between previous control inputs is used to stabilize the system. A smoothing boundary layer is introduced into the system to eliminate the high frequency chattering of the control input and the higher order states. The [B] matrix used in the model-free algorithm based on the sliding mode control is derived for a quadcopter system. A simulation of a quadcopter is built in Simulink and the model-free control algorithm based on sliding mode control is implemented and a PID control law is used to compare the performance of the model-free control algorithm based off of the RMS (Root-Mean-Square) of the difference between the actual state and the desired state as well as average power usage. The model-free algorithm outperformed the PID controller in all simulations with the quadcopter’s original parameters, double the mass, double the moments of inertia, and double both the mass and the moments of inertia while keep both controllers exactly the same for each simulation

PI-STA cascade controller tuning for active power filter applications

[EN] Typically, the control scheme of the active power filter corresponds to a cascade controller, which consists of an outer loop for dc voltage regulation and an inner loop for the tracking of a reference current. Each control loop must be associated with controllers that allow a fast convergence to the established references. This paper presents a cascade controller for active power filter applications, employing a proportional-integral (PI) controller for the external loop, and the super-twisting algorithm (STA) for the internal loop, where the union of both controllers is called PI-STA cascade controller. On the one hand, a step response analysis for the estimation PI gains is carried out. On the other hand, the STA tuning takes place from considering the similarity between the structures of STA with a PI. In order to validate the methodology tuning consistency simulation and experimental results are presented.[ES] Típicamente el esquema de control de un filtro activo de potencia corresponde a un controlador en cascada, el cual consta de un lazo externo para la regulación del voltaje de cd y un lazo interno para el seguimiento de una corriente de referencia. Cada uno de estos lazos de control está asociado a un controlador que permite converger rápidamente a su respectiva referencia. Este trabajo emplea un controlador PI en el lazo externo y el algoritmo Super-Twisting (STA) en el lazo interno, los cuales conforman al controlador en cascada denotado como PI-STA. Este artículo presenta una metodología para sintonizar los controladores PI y STA, donde el primero se sintoniza a partir de la respuesta al escalón, mientras el STA se sintoniza a partir de considerar la similitud de su estructura con respecto a la de un PI, facilitando así la obtención de las ganancias del STA. Para validar la metodología de sintonización, se presentan resultados en simulación y experimentales.Se agradece al Instituto Tecnológico de Sonora (ITSON) por los fondos proporcionados a través de los programas PROFAPI y PFCE para la construcción del prototipo experimental.Terán, R.; Pérez, J.; Beristáin, J.; Cárdenas, V. (2020). Sintonización del controlador en cascada PI-STA para aplicaciones de filtros activos de potencia. Revista Iberoamericana de Automática e Informática industrial. 17(2):130-143. https://doi.org/10.4995/riai.2020.12403OJS130143172Ammar, Abdelkarim, et al. "Closed Loop Torque SVM-DTC Based on Robust Super Twisting Speed Controller for Induction Motor Drive with Efficiency Optimization." International Journal of Hydrogen Energy, vol. 42, no. 28, Pergamon, July 2017, pp. 17940-52. https://doi.org/10.1016/j.ijhydene.2017.04.034Asadi, M., Ebrahimirad, H., Mousavi, M. S., & Jalilian, A. (2016). Sliding mode control of dc-link capacitors voltages of a NPC 4-wire shunt active power filter with selective harmonic extraction method. In 7th Power Electronics, Drive Systems and Technologies Conference, PEDSTC 2016 (pp. 273-278). Institute of Electrical and Electronics Engineers Inc. https://doi.org/10.1109/PEDSTC.2016.7556873Boubzizi, Said, et al. "Cascaded Adaptive Super Twisting Controller for DC/DC Converters in Electrical Vehicle Applications." IECON 2018 - 44th Annual Conference of the IEEE Industrial Electronics Society, IEEE, 2018, pp. 2007-14. https://doi.org/10.1109/IECON.2018.8591380Costa, Bruno Leandro Galvao, et al. "Tuning of a PI-MR Controller Based on Differential Evolution Metaheuristic Applied to the Current Control Loop of a Shunt-APF." IEEE Transactions on Industrial Electronics, vol. 64, no. 6, June 2017, pp. 4751-61. https://doi.org/10.1109/TIE.2017.2674609Del Pizzo, Andrea, et al. "Super Twisting Sliding Mode Control of Smart-Inverters Grid-Connected for PV Applications." 2017 6th International Conference on Renewable Energy Research and Applications, ICRERA 2017, vol. 2017-Janua, IEEE, 2017, pp. 793-96. https://doi.org/10.1109/ICRERA.2017.8191168Enrique, Luis, et al. "Integral Nested Sliding Mode Control for Robotic Manipulators." IFAC Proceedings Volumes, vol. 41, no. 2, Elsevier, Jan. 2008, pp. 9899-904. https://doi.org/10.3182/20080706-5-KR-1001.01675Galan, Nestor Daniel, et al. "Application of PI and Super Twisting Drivers to Voltage Regulation of Wind Farm via StatCom." IEEE Latin America Transactions, vol. 13, no. 2, Feb. 2015, pp. 462-68. https://doi.org/10.1109/TLA.2015.7055565Gonzalez, O., et al. "Unity Power Factor Rectifier with Reactive and Harmonic Current Compensation." 2016 13th International Conference on Power Electronics (CIEP), IEEE, 2016, pp. 238-42. https://doi.org/10.1109/CIEP.2016.7530763Jayathilaka, Imanka, et al. "DQ Transform Based Current Controller for Single-Phase Grid Connected Inverter." 2018 2nd International Conference On Electrical Engineering (EECon), IEEE, 2018, pp. 32-37. https://doi.org/10.1109/EECon.2018.8541004Khalil, H. (2015). Nonlinear Control.Komurcugil, Hasan. "Improved Passivity-Based Control Method and Its Robustness Analysis for Single-Phase Uninterruptible Power Supply Inverters." IET Power Electronics, vol. 8, no. 8, 2015, pp. 1558-70. https://doi.org/10.1049/iet-pel.2014.0706Liserre, Marco, et al. "Multiple Harmonics Control for Three-Phase Grid Converter Systems with the Use of PI-RES Current Controller in a Rotating Frame." IEEE Transactions on Power Electronics, vol. 21, no. 3, 2006, pp. 836-41. https://doi.org/10.1109/TPEL.2006.875566Mane, M., & Namboothiripad, M. K. (2016). Current harmonics reduction using sliding mode control based shunt active power filter. In Proceedings of the 10th International Conference on Intelligent Systems and Control, ISCO 2016. Institute of Electrical and Electronics Engineers Inc. https://doi.org/10.1109/ISCO.2016.7727005Mane, M., & Namboothiripad, M. K. (2017). PWM based sliding mode controller for shunt active power filter. In 2017 International Conference on Nascent Technologies in Engineering (ICNTE) (pp. 1-6). IEEE. https://doi.org/10.1109/ICNTE.2017.7947964Mina, J. (2002). Stability Analysis for a Single Phase Active Shunt Power Filter. Retrieved December 15, 2019, from https://www.researchgate.net/publication/331962956_Stability_Analysis_for_a_Single_Phase_Active_Shunt_Power_FilterOchoa Robles, Obed Enrique, et al. "Reactive Power Compensation in a Photovoltaic Grid Tie System, Using a Single-Phase Bidirectional High Frequency Link Converter." IEEE Latin America Transactions, vol. 14, no. 4, Apr. 2016, pp. 1816-21. https://doi.org/10.1109/TLA.2016.7483520Pérez Ramírez, Javier. Electrónica de Potencia: Modelado y Control de Convertidores Cd-Cd. 2016.Ramírez, Jorge, et al. "High Order Sliding Mode Control for Shunt Active Power Filter." 2015 IEEE International Autumn Meeting on Power, Electronics and Computing, ROPEC 2015, IEEE, 2016, pp. 1-6. https://doi.org/10.1109/ROPEC.2015.7395111Sadeghi, R., Madani, S. M., Ataei, M., Agha Kashkooli, M. R., & Ademi, S. (2018). Super-twisting sliding mode direct power control of a brushless doubly fed induction generator. IEEE Transactions on Industrial Electronics, 65(11), 9147-9156. https://doi.org/10.1109/TIE.2018.2818672Shtessel, Y., Edwards, C., Fridman, L., & Levant, A. (2014). Sliding Mode Control and Observation. https://doi.org/10.1016/j.chaos.2007.09.095Shu, Zeliang, et al. "Specific Order Harmonics Compensation Algorithm and Digital Implementation for Multi-Level Active Power Filter." IET Power Electronics, vol. 10, no. 5, Apr. 2017, pp. 525-35. https://doi.org/10.1049/iet-pel.2016.0315Society, IEEE Power &. Energy. 1459-2010 IEEE Standard Definitions for the Measurement of Electric Power Quantities Under Sinusoidal, Nonsinusoidal, Balanced, or Unbalanced Conditions. 2010, https://ieeexplore.ieee.org/document/5439063.Teran, R. A. J., et al. "TUNING METHODOLOGY FOR PI CONTROLLERS IN ACTIVE POWER FILTERS." DYNA Energía y Sostenibilidad, vol. 8, no. 1, 2019, pp. 1-11. https://doi.org/10.6036/ES922

Aerial Robotics for Inspection and Maintenance

Aerial robots with perception, navigation, and manipulation capabilities are extending the range of applications of drones, allowing the integration of different sensor devices and robotic manipulators to perform inspection and maintenance operations on infrastructures such as power lines, bridges, viaducts, or walls, involving typically physical interactions on flight. New research and technological challenges arise from applications demanding the benefits of aerial robots, particularly in outdoor environments. This book collects eleven papers from different research groups from Spain, Croatia, Italy, Japan, the USA, the Netherlands, and Denmark, focused on the design, development, and experimental validation of methods and technologies for inspection and maintenance using aerial robots

Proceedings of the NASA Conference on Space Telerobotics, volume 4

Papers presented at the NASA Conference on Space Telerobotics are compiled. The theme of the conference was man-machine collaboration in space. The conference provided a forum for researchers and engineers to exchange ideas on the research and development required for the application of telerobotic technology to the space systems planned for the 1990's and beyond. Volume 4 contains papers related to the following subject areas: manipulator control; telemanipulation; flight experiments (systems and simulators); sensor-based planning; robot kinematics, dynamics, and control; robot task planning and assembly; and research activities at the NASA Langley Research Center