Linshuai Zhang

Design and performance evaluation of collision protection-based safety operation for a haptic robot-assisted catheter operating system

The robot-assisted catheter system can increase operating distance thus preventing the exposure radiation of the surgeon to X-ray for endovascular catheterization. However, few designs have considered the collision protection between the catheter tip and the vessel wall. This paper presents a novel catheter operating system based on tissue protection to prevent vessel puncture caused by collision. The integrated haptic interface not only allows the operator to feel the real force feedback, but also combines with the newly proposed collision protection mechanism (CPM) to mitigate the collision trauma. The CPM can release the catheter quickly when the measured force exceeds a certain threshold, so as to avoid the vessel puncture. A significant advantage is that the proposed mechanism can adjust the protection threshold in real time by the current according to the actual characteristics of the blood vessel. To verify the effectiveness of the tissue protection by the system, the evaluation experiments in vitro were carried out. The results show that the further collision damage can be effectively prevented by the CPM, which implies the realization of relative safe catheterization. This research provides some insights into the functional improvements of safe and reliable robot-assisted catheter systems.

Design and principle analysis for electromagnetic brake clamping mechanism of a novel slave manipulator

Robotically assisted catheterization has attracted significant interest in recent years. However, few designs have taken the reasonable control of the clamping force into consideration. Additionally, limited research has been conducted in the damage of the clamping mechanism to the catheter. This paper presents a novel clamping mechanism for a slave manipulator that can be used in the minimally invasive surgery training system. The clamping mechanism utilizes the electromagnetic force which generated by the electrified coil to balance the pressure provided by the compression spring. Also the clamping force can be adjusted by the input current to prevent excessive clamping or inadequate clamping for the catheter. In addition, the modal analysis of the designed clamping structure is carried out. The results show that the modal frequency of the clamping structure is very small, so it does not resonate with the external excitation when the catheter is pushed forward. This clamping mechanism provides important insights into the design of compact and ergonomic robotic catheter manipulators incorporating effective and lossless clamping for intraoperative navigation.

MR fluid interface of endovascular catheterization based on haptic sensation

During the teleoperated robot assisted catheter interventional neurosurgery, to improve the transparency between the patient side (slave side) and the remote control side (mast side) have been obtained plenty of attention. In this research we hypothesized that the slave catheter interventional robot fully complied with the dynamics command which comes from the master site. This paper is concerned with the design and implementation of a master side by Magnetorheological (MR) fluid, which can reflect the dynamic changes of the insertion resistance force, when the catheter goes through the blood vessel to the lesions. Experimental results showed that MR Fluid actuated haptic interface has a benefit to describe the blood viscous force during the endovascular catheterization.

Performance evaluation of a robot-assisted catheter operating system with haptic feedback

In this paper, a novel robot-assisted catheter operating system (RCOS) has been proposed as a method to reduce physical stress and X-ray exposure time to physicians during endovascular procedures. The unique design of this system allows the physician to apply conventional bedside catheterization skills (advance, retreat and rotate) to an input catheter, which is placed at the master side to control another patient catheter placed at the slave side. For this purpose, a magnetorheological (MR) fluids-based master haptic interface has been developed to measure the axial and radial motions of an input catheter, as well as to provide the haptic feedback to the physician during the operation. In order to achieve a quick response of the haptic force in the master haptic interface, a hall sensor-based closed-loop control strategy is employed. In slave side, a catheter manipulator is presented to deliver the patient catheter, according to position commands received from the master haptic interface. The contact forces between the patient catheter and blood vessel system can be measured by designed force sensor unit of catheter manipulator. Four levels of haptic force are provided to make the operator aware of the resistance encountered by the patient catheter during the insertion procedure. The catheter manipulator was evaluated for precision positioning. The time lag from the sensed motion to replicated motion is tested. To verify the efficacy of the proposed haptic feedback method, the evaluation experiments in vitro are carried out. The results demonstrate that the proposed system has the ability to enable decreasing the contact forces between the catheter and vasculature.

Haptic feedback in robot-assisted endovascular catheterization

In teleoperated robot-assisted catheter intervenetional surgery, haptic feedback allows the interventionalist to perceive the remote contact force between the catheter and blood vessel. In this research, the haptic feedback in axial direction has been provided to the operator in master site to guide the remote catheter insertion. A remote catheter navigation system was presented, and the MR (Magnetorheological) fluids based haptic interface was as the master site. To evaluate the performance of the haptic feedback in catheter insertion, ten subjects were recruited to manipulate designed remote catheter navigation system. The patient catheter went through the blood vessel phantom, and the dynamic changes of the insertion resistance force can be measured by catheter manipulator in slave site which will be perceived by the operator through the master haptic interface. Experimental results showed that haptic feedback has a benefit to decreasing the contact force between the catheter and blood vessel phantom during the remote catheter navigation.

Electromagnetic braking-based collision protection of a novel catheter manipulator

A robotically assisted catheterization system can obviously reduce the radiation exposure to the surgeon and lesson the fatigue caused by standing for long time in protective clothing. However, few designs have taken the collision protection function of a catheter manipulator into consideration. Additionally, limited research has been conducted in the damage of the clamping mechanism to the catheter. This paper presents a novel clamping mechanism based on the electromagnetic braking for a catheter manipulator which can be used in the minimally invasive surgery training system. A significant advantage is that the proposed design has the collision protection function which can realize the relative sliding between the catheter and the clamping device so as to avoid the vessel puncture, when the measured force exceeds a certain threshold. In addition, the simulation verification of this function is carried out. The results show that the clamping force of the catheter obviously decreases when the measured force increases. This clamping mechanism provides important insights into the design of safe and reliable robotic catheter manipulators incorporating effective and lossless clamping for intraoperative navigation.

A hybrid propulsion device for the spherical underwater robot (SUR III)

The propulsion system as the main power for the underwater robot will extremely influence its hydrodynamic performance. This paper focuses on a novel hybrid propulsion device for the third-generation spherical underwater robot (SUR III) with both vectored water-jet thrusters and propeller thrusters. To the limited space and mechanism, the hybrid propulsion device not only reserves the symmetric structure to maintain balance underwater, but also enhances the better property. And the diversity of the movement is also proposed for the different target as remote or hover. In order to analyze the hydrodynamic characteristics of the propeller, we establish the flow field with the multi-reference frame method to calculate the pressure and thrust of the propeller in ANSYS CFX. Finally, we set up the experimental system with a 6-DOFs load cell to measure the thrust of the propeller. Comparing the simulation and experiment results, the simulation thrust error is less than 8.5%. Meanwhile the power of the propeller thruster is 22.5% better than the water-jet thruster.

The virtual reality simulator-based catheter training system with haptic feedback

The endovascular surgery benefits patients due to the miniature wound and fast healing, but to achieve this kind of goal need the doctor with superb skill in order to not made damage to the patients. A training system is desperately in need. The training system is cooperated with VR simulator system, which could simulate the movement of the catheter. To get the novice surgeons get trained, a controlling device makes training system effective. At the same time, the feedback system also provides advantages for training. The performance is evaluated from the displacement in VR system and force feedback from haptic device. The results demonstrate that the operation error is less than 10%. The purposed training system provides a effective way which combined the VR catheter system and force feedback system.