Modeling of Laparoscopic Forceps with Sensing

Progress of minimally invasive surgery stimulates the development of sensory techniques. The present study is related with creation of a mechatronic clamping laparoscopic device (forceps) that allows transferring tactile sensations from the jaws of the clamp to the handles of the master manipulator operated by surgeon. The user presses the handles of the manipulator. The change in the angle between the handles is synchronized with the change in the angle between the jaws of the forceps (slave link) that grasps the soft tissue. The contact load is identified based on the voltage applied to the electric motor connected to the forceps and then transferred to the control unit. This control unit adjusts the operating frequency of the piezoelectric actuator in such a way as to generate a force corresponding to the measured load. This force is applied to handles of the manipulator. It creates a moment in the handle, which is felt by the user. Thus, the system provides the tactile feedback. In order to describe the dynamics of the piezoelectric actuator, a finite-dimensional empirical model is used. In order to describe the dependence of the moment, with which the soft tissue acts upon the jaws of forceps, on the span angle between the forceps, a mathematical model is proposed. This model takes into account the properties of the soft tissue (which is assumed elastic) and geometry of the surface of forceps jaws. An algorithm for identification of the moment acting from the tissue on the forceps is proposed. Numerical simulation of dynamics of the system is performed. The results of calculations confirm the efficiency of the algorithm for identifying the moment created by tissue.

1. Kurita Yu., Tsuji T., Kawahara T., Okajima M., Egi H., Ohdan H., Ogasawara T. Force-based Automatic Classification of Basic Manipulations with Grasping Forceps, International Journal of Life Science and Medical Research, 2013, vol. 4, iss. 2, pp. 76—82.

2. Radó J., Dücso˝ C., Földesy P., Szebényi G., Nawrat Z.,

3. Rohr K., Fürjes P. 3D force sensors for laparoscopic surgery tool, Microsyst. Technol, 2018, vol. 24, pp. 519—525, available at: https:// doi.org/10.1007/s00542-017-3443-4.

4. Galin L. A. Kontaktnyye zadachi teorii uprugosti i vyazkouprugosti (Contact problems of the theory of elasticity and viscoelasticity), Мoscow, Nauka, 1980, 304 p. (in Russian).

5. Johnson K. L. Contact Mechanics, Cambridge University Press, 1985.

6. Goryacheva I. G. Mekhanika friktsionnogo vzaimodeystviya. (Mechanics of friction interaction), Мoscow, Nauka, 2001, 478 p. (in Russian).

7. Sadovnichiy V., Goryacheva I., Akaev A., Martynenko Yu., Okunev Yu., Vlakhova A., Bogdanovich I. Primeneniye metodov mekhaniki kontaktnykh vzaimodeystviy pri diagnostike patologicheskikh sostoyaniy myagkikh biologicheskikh tkaney (The use of contact mechanics methods in the diagnosis of pathological states of soft biological tissues), Moscow, MSU Publishing, 2009, 306 p. (in Russian).

8. Dosaev M. Z., Selyutskiy Yu.D., Yeh C.-H., Su F.-C. Modelirovaniye taktil’noy obratnoy svyazi, realizuyemoy s pomoshch’yu p’yezoelektricheskogo privoda (Simulation of tactile feedback, implemented using a piezoelectric actuator), Mekhatronika, Avtomatizatsiya, Upravlenie, 2018, vol. 19, no.7, pp. 480—485 (in Russian).

9. Wurpts W., Twiefel J. An ultrasonic motor with intermittent contact modeled as a two degree of freedom oscillator in time domain, PAMM, 2009, vol. 9, pp. 287—288, doi: 10.1002/pamm.200910117.

10. Mashimo T., Terashima K. Dynamic analysis of an ultrasonic motor using point contact model, Sensors and Actuators A: Physical, 2015, vol. 233, pp. 15—21, doi: 10.1016/j.sna.2015.05.009.

11. Liu Z., Yao Z., Li X., Fu Q. Design and experiments of a linear piezoelectric motor driven by a single mode, Review of Scientific Instruments, 2016, vol. 87v 115001; doi: 10.1063/1.4966251.

12. Yakovenko A. A. Simulation of contact interaction of a gripping tool with a biological tissue, Russian Journal of Biomechanics, Perm National Research Polytechnic University, Perm, Russian Federation, 2017, vol. 21, no. 4, pp. 355—364.