A Cost-Effective and Smart Sensing Tissue-like Testbed for Surgical Training

A low-cost tissue-like testbed with six nodes of varying stiffness was developed for surgical training to provide pressure and force feedback data through image reception to human operators. Using SolidWorks, a 3D model of the box trainer housing was created. A pad for the distribution of smartsensing nodes and microcontroller connections was designed with open spaces for the respective components. The pad was 3D-printed with PLA filament. Flat piezoelectric pressure sensors were fabricated with conductive materials and velostat sensor material. Using static and dynamic analyses, three top sensors were chosen to be used in three pressure sensing nodes. A calibration process was performed on the pressure sensors to find the linear relationship between voltage and pressure, which was then used to create a conversion equation for each sensor. These equations were used to collect data at the three pressure sensing nodes on the silicone testbed pad. Conductive TPU filament was used to 3D-print vertical force sensors, which were designed using SolidWorks. The force sensors were calibrated with a squeezing mechanism to find a relationship between voltage and force and to subsequently develop a conversion equation for each sensor. We used these equations to collect force data from the three force sensing nodes on the testbed pad. Through static and dynamic analyses, the force sensors were found to be functional, but to need improvements in accuracy. The mechatronic system was designed and developed to integrate all six sensors and to collect data from the testbed pad using an Arduino microcontroller. The flat pressure and vertical force sensors were embedded in each node to measure the pressure and force that occurs during the deformation of the six nodes. Data was collected and imported into MATLAB. This data was used in displaying pressure and force mapping of the nodes over a live video of the silicone pad. Pressure and force mapping was realized by drawing color-coded circles on each of the six nodes that correspond to a range of force or pressure values. From this development, the surgical testbed provides multi-stiffness tissue training with live pressure and force mapping overlaid on a live video of the emulated surgical field

Robust teleoperation of mechanical systems based on active disturbances compensation control structure

[EN] We present a control strategy to guarantee the stability of teleoperation systems formed by mechanical systems of nDOF with parametric uncertainties, external disturbances, a partial measure of state vectors, and without the use of force sensors. We neglected time delays in the communication channel, because we assume that mechanical systems are close enough. The control strategy is based on the disturbances active compensation structure, which incorporates discontinuous state observers and low-pass filters to estimate state variables and all nonmeasured signals needed to implement the controller. The controller is robust such that guarantees the tracking control objective. The teleoperation strategy’s performance is illustrated by experiments with mechanical systems of one and two degrees of freedom.[ES] Se presenta una estrategia de control para garantizar la estabilidad de sistemas de teleoperación formados por mecanismos de n grados de libertad (nGDL), con incertidumbres paramétricas, perturbaciones externas, medición parcial de los vectores de estado y sin el uso de sensores de fuerza. Se asume que los mecanismos se encuentran lo suficientemente cercanos uno del otro, de tal forma que el problema de retardos ocasionados por el medio de comunicación es despreciable. La estrategia se basa en la aplicación de la estructura de control con compensación activa de perturbaciones, la cual incorpora observadores de estado discontinuos y filtros paso bajo que permiten la estimación de las variables de estado y otras señales no medidas, así como los términos de perturbación presentes en ambos sistemas, que permiten la implementación de los controladores. El desempeño de la estrategia de teleoperación se ilustra a través de experimentos con mecanismos de uno y dos grados de libertad.Rosas Almeida, D.; González Solis, E.; Raya Díaz, G. (2021). Teleoperación robusta de sistemas mecánicos basada en la estructura de control con compensación activa de perturbaciones. Revista Iberoamericana de Automática e Informática industrial. 18(3):218-229. https://doi.org/10.4995/riai.2021.14433OJS218229183Almeida, D. I. R., Álvarez, J., Peña, J., 2011. Control structure with disturbance identification for lagrangian systems. International Journal of Non-Linear Mechanics 46, 486-495. https://doi.org/10.1016/j.ijnonlinmec.2010.08.005Almeida, D. I. R., Cárdenas, J. A. C., Díaz, J. d. D. O., Valdez, H. M., 2019. Control robusto de un actuador neumático basado en la estructura de control con compensación activa de perturbaciones para seguimiento de trayectorias. Revista Iberoamericana de Automática e Informática industrial 16, 138-146. https://doi.org/10.4995/riai.2018.9073Chan, L., Naghdy, F., Stirling, D., 2014. Application of adaptive controllers in teleoperation systems: A survey. IEEE Transactions on Human-Machine Systems 44, 337-352. https://doi.org/10.1109/THMS.2014.2303983De Lima, M. V., Mozelli, L. A., Neto, A. A., Souza, F. O., 2020. A simple algebraic criterion for stability of bilateral teleoperation systems under timevarying delays. Mechanical Systems and Signal Processing 137, 106217. https://doi.org/10.1016/j.ymssp.2019.06.035Erickson, D., Weber, M., Sharf, I., 2003. Contact stiffness and damping estimation for robotic systems. The International Journal of Robotics Research 22, 41-57. https://doi.org/10.1177/0278364903022001004Fink, N., 2019. Model reference adaptive control for telemanipulation. Hungarian Journal of Industry and Chemistry 47, 41-48. https://doi.org/10.33927/hjic-2019-07Li, Y., Liu, K., He, W., Yin, Y., Johansson, R., Zhang, K., 2019. Bilateral teleoperation of multiple robots under scheduling communication. IEEE Transactions on Control Systems Technology. https://doi.org/10.1109/TCST.2019.2923788Mohammadi, A., Tavakoli, M., Marquez, H. J., 2012. Control of nonlinear teleoperation systems subject to disturbances and variable time delays. In: Editor (Ed.), 2012 IEEE/RSJ International Conference on Intelligent Robots and Systems. Vol. II. IEEE, Ch. 7, pp. 3017-3022. https://doi.org/10.1109/IROS.2012.6385461Passenberg, C., Peer, A., Buss, M., 2010. A survey of environment-, operator- , and task-adapted controllers for teleoperation systems. Mechatronics 20, 787-801. https://doi.org/10.1016/j.mechatronics.2010.04.005Rasouli, P., Forouzantabar, A., Moattari, M., Azadi, M., 2020. Fault-tolerant control of teleoperation systems with flexible-link slave robot and disturbance compensation. Iranian Journal of Science and Technology, Transactions of Electrical Engineering, 1-13. https://doi.org/10.1007/s40998-020-00309-5Rodriguez-Angeles, A., Nijmeijer, H., 2004. Mutual synchronization of robots via estimated state feedback: a cooperative approach. IEEE Transactions on control systems technology 12, 542-554. https://doi.org/10.1109/TCST.2004.825065Rosas, D. I., Álvarez, J., Cantú Cárdenas, J. A., 2019. Application of the active disturbance rejection control structure to improve the controller performance of uncertain pneumatic actuators. Asian Journal of Control 21, 99-113. https://doi.org/10.1002/asjc.2026Rosas, D. I., Álvarez, J., Fridman, L., 2007. Robust observation and identification of ndof lagrangian systems. International Journal of Robust and Nonlinear Control: IFAC-Affiliated Journal 17, 842-861. https://doi.org/10.1002/rnc.1156Sánchez-Sánchez, P., Gutiérrez-Giles, A., Pliego-Jiménez, J., Arteaga-Pérez, ' M., 2019. Seguimiento de trayectorias con incertidumbre del modelo usando un diferenciador robusto. Revista Iberoamericana de Automática e Informática. 16, 423-434. https://doi.org/10.4995/riai.2019.10265Utkin, V., 1977. Variable structure systems with sliding modes. IEEE Transactions on Automatic control 22, 212-222. https://doi.org/10.1109/TAC.1977.1101446Yang, H., Liu, L., Wang, Y., 2019. Observer-based sliding mode control for bilateral teleoperation with time-varying delays. Control Engineering Practice 91, 104097. https://doi.org/10.1016/j.conengprac.2019.07.01

Bilateral Teleoperation of Multiple Robots under Scheduling Communication

In this paper, bilateral teleoperation of multiple slaves coupled to a single master under scheduling communication is investigated. The sampled-data transmission between the master and the multiple slaves is fulfilled over a delayed communication network, and at each sampling instant, only one slave is allowed to transmit its current information to the master side according to some scheduling protocols. To achieve the master-slave synchronization, round-robin (RR) scheduling protocol and try-once-discard (TOD) scheduling protocol are employed, respectively. By designing a scheduling-communication-based controller, some sufficient stability criteria related to the controller gain matrices, sampling intervals, and communication delays are obtained for the closed-loop teleoperation system under the RR and TOD scheduling protocols, respectively. Finally, simulation studies are given to validate the effectiveness of the proposed results