Modeling and control of a high-precision tendon-based magnetic resonance imaging–compatible surgical robot

Abstract

This article mainly includes the developing, dynamical modeling and control of a tendon-based robot system. First, a 5-degree-of-freedom tendon-based magnetic resonance imaging–compatible robot for prostate needle insertion surgery is introduced briefly. What follows is the dynamical modeling of the robot system, where a mechanical dynamic model is established using the Lagrange method, and a lumped parameter tendon model is used to identify the nonlinear gain of the actuator. Based on the dynamical model, a fuzzy sliding mode control algorithm is proposed for accurate position control of the robot. Through simulations using different sinusoidal input signals, we observed that the sinusoidal tracking error at 1/2π Hz is 0.2 mm and the needle tip positional precision of tracking a spatial arched curve remains less than 0.3 mm. Finally, experiments on tendon-sheath transmission and robot position tracking are conducted, which shows that the insertion precision is 0.67 mm in laboratory environment.

Design and analysis of a tendon-based computed tomography–compatible robot with remote center of motion for lung biopsy

“…Notably, as to the orientation module, tendon-sheath transmission is another error source. In previous research, 15,21 a deep and detailed study has been carried out to offset position error caused by hysteresis behavior, nonlinear characteristics and the friction between the tendon and the sheath. For the robot in this article, the same method is applied to offset transmission system.…”

“…Pneumatic and flexible shaft are too large in structure to be applied in the narrow space. To avoid complex structure and kinematics, 19,20 tendon–sheath method 15,21 is applied in the orientation module. The schematic of tendon–sheath is shown in Figure 5.…”

“…The resolution of lead screw is 0.01 mm in the position module, and the error of tendon–sheath transmission system is less than 0.55 mm in previous research. 15,21 In the case of the CT-compatible robot, the error model is applied to investigate the deviation caused by two types of error sources, respectively. As shown in Figure 14, the deviations caused by two reasons are different in directions and values indicated by 20 points of the needle tip in workspace.…”

Structural design and analysis of pneumatic prostate seed implantation robot applied in magnetic resonance imaging environment

“…Bomers et al 26 developed a prostate seed implantation robot composed of plastic parts; the robot is driven by a pneumatic stepping motor (the actuator adopts the principle of pumping/ exhausting), which can realize fast and accurate positioning steps for the puncture needle, and is combined with an independent computer for planning and remote control; but, the robot is susceptible to strong magnetic interference, and it is easy to cause large errors if long-distance pneumatic transmission is used, and due to the tightness of the plastic drive cylinder of the robot, it will not be able to transmit a large torque for deep puncture. In addition, Guo et al 27 developed a bilateral stereotaxic robot that can be guided by magnetic resonance images in surgery; this robot adopts hydraulic drive and can work in a small MRI space; however, this robot does not solve the problem of hydraulic sealing very well, and hydraulic oil leakage in a real operation will cause a great safety threat to the patient.…”