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. 2017 Sep 30;17(10):2257.
doi: 10.3390/s17102257.

A Novel Position Compensation Scheme for Cable-Pulley Mechanisms Used in Laparoscopic Surgical Robots

Yunlei Liang  1 , Zhijiang Du  2 , Weidong Wang  3 , Lining Sun  4
Affiliations

A Novel Position Compensation Scheme for Cable-Pulley Mechanisms Used in Laparoscopic Surgical Robots

Yunlei Liang et al. Sensors (Basel). .

Abstract

The tendon driven mechanism using a cable and pulley to transmit power is adopted by many surgical robots. However, backlash hysteresis objectively exists in cable-pulley mechanisms, and this nonlinear problem is a great challenge in precise position control during the surgical procedure. Previous studies mainly focused on the transmission characteristics of the cable-driven system and constructed transmission models under particular assumptions to solve nonlinear problems. However, these approaches are limited because the modeling process is complex and the transmission models lack general applicability. This paper presents a novel position compensation control scheme to reduce the impact of backlash hysteresis on the positioning accuracy of surgical robots' end-effectors. In this paper, a position compensation scheme using a support vector machine based on feedforward control is presented to reduce the position tracking error. To validate the proposed approach, experimental validations are conducted on our cable-pulley system and comparative experiments are carried out. The results show remarkable improvements in the performance of reducing the positioning error for the use of the proposed scheme.

Keywords: backlash hysteresis; cable-pulley system; position compensation; support vector machine.

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Conflict of interest statement

The authors declare no conflict of interest.

Figures

Figure 1
Figure 1
Some surgical robot instruments.
Figure 2
Figure 2
The relationship between actual and command angular displacement: segments ab and cd represent backlash hysteresis; segments bc and ad represent normal movement.
Figure 3
Figure 3
The robotic arm and surgical instrument studied in this paper.
Figure 4
Figure 4
The cable-pulley system studied in this paper.
Figure 5
Figure 5
The simplified physical model of the cable-pulley system.
Figure 6
Figure 6
Varying patterns of motor driving moment and motor current: (a) varying patterns of motor driving moment; (b) varying patterns of motor current.
Figure 7
Figure 7
The result of FFT for the first non-zero frequency.
Figure 8
Figure 8
The position compensation control scheme based on SVM.
Figure 9
Figure 9
Photo of experimental setup.
Figure 10
Figure 10
Introduction of the experiment system.
Figure 11
Figure 11
Initial selected features for SVM.
Figure 12
Figure 12
The classification effect of the movement stage when the motor runs in different motion patterns: (a) Uniform motion; (b) Uniform accelerated motion; (c) Variable accelerated motion; (d) Sinusoidal wave motion.
Figure 13
Figure 13
Edge extraction results of the images grabbed by the camera: (a) The sub-pixel precise edges of the end-effector’s tip; (b) The bottom edge of the end-effector’s tip.
Figure 14
Figure 14
Comparison between the actual angular displacement of the end-effector with and without position compensation.
Figure 15
Figure 15
The position error of each cycle.
See this image and copyright information in PMC

References

    1. Du Z., Wang W., Yan Z., Dong W., Wang W. Variable admittance control based on fuzzy reinforcement learning for minimally invasive surgery manipulator. Sensors. 2017;17:844. doi: 10.3390/s17040844. - DOI - PMC - PubMed
    1. DiMaio S., Hanuschik M., Kreaden U. Surgical Robotics. Springer; Berlin, Germany: 2011. The da Vinci surgical system; pp. 199–217.
    1. Guiochet J., Tondu B., Baron C. Integration of UML in human factors analysis for aafety of a medical robot for tele-echography; Proceedings of the 2003 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS 2003); Las Vegas, NV, USA. 27–31 October 2003; pp. 3212–3217.
    1. Giulianotti P.C., Coratti A., Angelini M., Sbrana F., Cecconi S., Balestracci T., Caravaglios G. Robotics in general surgery: Personal experience in a large community hospital. Arch. Surg. 2003;138:777–784. doi: 10.1001/archsurg.138.7.777. - DOI - PubMed
    1. Murphy D.A., Miller J.S., Langford D.A., Snyder A.B. Endoscopic robotic mitral valve surgery. J. Thorac. Cardiovasc. Surg. 2006;132:776–781. doi: 10.1016/j.jtcvs.2006.04.052. - DOI - PubMed