Zhang Haijun

Bio: Zhang Haijun is an academic researcher from Jilin University. The author has contributed to research in topics: Surgical instrument & Robot end effector. The author has an hindex of 4, co-authored 10 publications receiving 35 citations.

New remote centre of motion mechanism for robot-assisted minimally invasive surgery

Abstract: Robot-assisted minimally invasive surgery (RMIS) is promising for improving surgical accuracy and dexterity. As the end effector of the robotic arm, the remote centre of motion mechanism is one of the requisite terms for guaranteeing patient safety. The existing remote centre of motion mechanisms are complex and large in volume, as well as high assembly requirement and unsatisfactory precise. This paper aimed to present a new remote centre of motion mechanism for solving these problems. A new mechanism based on the RMIS requirements is proposed for holding the laparoscope and generating a remote centre of motion for the laparoscope. The mechanism kinematics is then analysed from the perspective of the structural function, and its inverse kinematics is determined with a small number of calculations. Finally, the position deviation of the laparoscope rotational point is chosen as the index to evaluate the mechanism performance. The experiments are performed to test the deviation. The position deviations of the laparoscope rotational point do not exceed 2 mm, which is lower than that of the existing remote centre of motion mechanism. The 2 mm positioning error of the laparoscope won’t affect surgeon observation of the surgical field, and the pressure caused by the positioning error was acceptable for the skin elasticity. The proposed mechanism meets the RMIS requirement. The proposed mechanism can achieve the remote centre of motion for the laparoscope. Its simple and compact structure is beneficial to avoid the collision of robotic arms, and it can be applied on other robots for providing the instrument necessary motion in minimally invasive surgery.

Flexible multi-joint surgical instrument for robot assisted minimally invasive surgery

Abstract: The invention discloses a flexible multi-joint surgical instrument for robot assisted minimally invasive surgery, and relates to the technical field of enterocoelia minimally invasive surgery department medical facilities The instrument can achieve spatial displacement and positioning of tail end operating forceps by itself inside a patient, the tail end gesture adjusting capability of the surgical instrument is enhanced, the good flexibility is achieved, and the tissue surgical operation is completed inside the small space; by means of a self-rotation joint designed between the wrist of the surgical instrument and the tail end operating forceps, and the problem that joint restoration is needed during autorotation is avoided; the instrument comprises the tail end operating forceps mechanism, the autorotation joint, the wrist flexible joint and a power driving box; the power driving box comprises a wiring pipe, a shell, an upper base plate, a lower base plate, five sets of motor rope sheave devices, a rope guiding wheel set and a rope guiding column set; one end of the wiring pipe is connected with the tail end ball hinge structure of the wrist flexible joint, and the other end of the wiring pipe is fixed to the lower base plate The instrument is used for the robot assisted minimally invasive surgery

Minimally invasive surgery robot 7-degree freedom operation master manipulator

Abstract: The invention discloses a minimally invasive surgery robot 7-degree freedom operation master manipulator, and relates to a minimally invasive surgery robot; the operation master manipulator is used for solving the problems of complex structure and bad flexibility and university of the manipulator of the minimally invasive surgery robot. The master manipulator comprises a substrate, a turntable arranged on the substrate and rotated around a z axis, a link rod connected with the turntable and rotated around the x axis, a 1# self-rotating link rod connected with the link rod an rotated around the x axis, a 2# self-rotating link rod connected with the 1# self-rotating link rod and rotated around the x axis, and a clamping mechanism connected with the 2# self-rotating link rod; the clamping mechanism comprises a thumb part and an index finger part which are rotated face to face.

Robot for assisting minimally invasive surgery of pleuroperitoneal cavity

Abstract: The invention provides a robot for assisting a minimally invasive surgery of the pleuroperitoneal cavity and relates to a robot for clamping an endoscope and a surgical instrument in the minimally invasive surgery of the pleuroperitoneal cavity to overcome the shortcoming that in the traditional minimally invasive surgery process, unstable focus image display is caused by hand trembling and fatigue of an assistant due to long-time endoscope and surgical instrument holding, and a stable and continuous surgical drag force cannot be provided for the focus tissue. The robot comprises a base, a middle mechanical arm and side mechanical arms. The middle mechanical arm comprises a positioning joint and an end effector for clamping the endoscope. The positioning joint comprises a swing joint I, a swing joint II, a swing joint III and a swing joint IV. Each side mechanical arm comprises a swing joint V and a rotating joint. Each of the rotating joint and the five swing joints comprises a clutch, an encoder, a rotating shaft and a locking and swing measuring mechanism of a shaft sleeve. The robot is used for the minimally invasive surgery of the pleuroperitoneal cavity.

Biological soft tissue mechanical properties testing arrangement under cutting operation

Abstract: The utility model provides a biological soft tissue mechanical properties testing arrangement under cutting operation, it relates to a soft tissue mechanical properties testing arrangement to pre -tension's problem under the unable survey cutting operation of the current biological soft tissue mechanical properties testing arrangement of solution, and then according to experiment data collection,draw the required feature parameter that gets of mechanical model, establish soft tissue stress and strain's constitutive relation. It includes workstation, lift cutting device, horizontal tractive device and fixes the elevating platform of biological soft tissue, install the elevating platform of lift cutting device, horizontal tractive device and fixed biological soft tissue on the upper surfaceof workstation, the cutter is installed to lift cutting device's lift expansion end, and the elevating platform arranges under lift cutting device that the centre gripping has the biological soft tissue that is used for the mechanical properties test between the horizontal anomalous movement of horizontal tractive device end and the elevating platform. The utility model is used for test the mechanical properties of biological soft tissue under the cutting operation.

Development of a New Medical Robot System for Minimally Invasive Surgery

Abstract: This article presents the development of a new medical robot system comprising a spherical remote center motion (RCM) mechanism with modular design and two mechanical decoupling methods for Minimally Invasive Surgery (MIS). We achieved excellent comprehensive performance indices through a novel multi-objective optimization model comprising four optimization objective functions, three constrained conditions and two optimization variables. In order to enhance the manipulability, remove the coupling between motors, and reduce the control difficulty, two new decoupling mechanism means were proposed to remove coupling motion between the wrist and pincers, coupling motion between the translational joint of mobile platform and four interface disks of surgical instrument as a results of rear drive motor, respectively. The control system architecture is designed to include intuitive motion control, incremental motion control, and proportional motion control. Master-slave attitude registration and surgical instrument replacement strategies improve the master-slave control efficiency. We tested the spherical RCM mechanism performance indices and developed two mechanical decoupling methods and a master-slave control algorithm. Our experimental test results validated that fixing point accuracy, the coupling motions, the positioning and repeated positioning accuracy of the MIS robot, and master-slave control algorithm meet the requirements of MIS. Successful animal experiments confirmed effectiveness of the novel MIS robot system.

A Controller to Impose a RCM for Hands-on Robotic-Assisted Minimally Invasive Surgery

Abstract: In Robotic-Assisted Minimally Invasive Surgery a long and thin instrument attached to the robotic arm enters the human body through a tiny incision. To ensure that no injury occurs when the surgeon is manipulating the instrument, the incision point must be a remote center of motion (RCM) for the instrument. For this purpose, a novel target admittance model is designed in the joint space for hands-on procedures that can be applied in all commercially available general-purpose manipulators with six or more degrees of freedom. It is proved that the joint reference trajectories generated by the proposed target admittance model under the exertion of a human force are stable and satisfy the RCM constraint. The measurements of the human force and the robot’s forward kinematic model are only required. Its use spans all hands-on surgical procedures. The proposed model can be easily extended to achieve additional objectives. Simulation results validate the theoretical findings and experimental results utilizing a KUKA LWR4+ demonstrate that trocar displacements are less than 1mm.

Solving the Time-Varying Inverse Kinematics Problem for the Da Vinci Surgical Robot

Abstract: A dialytic-elimination and Newton-iteration based quasi-analytic inverse kinematics approach is proposed for the 6 degree of freedom (DOF) active slave manipulator in the Da Vinci surgical robot and other similar systems. First, the transformation matrix-based inverse kinematics model is derived; then, its high-dimensional nonlinear equations are transformed to a high-order nonlinear equation with only one unknown variable by using the dialytic elimination with a unitary matrix. Finally, the quasi-analytic solution is eventually obtained by the Newton iteration method. Simulations are conducted, and the result show that the proposed quasi-analytic approach has advantages in terms of accuracy (error < 0.00004 degree (or mm)), solution speed (<20 ms) and is barely affected by the singularity during intermediate calculations, which proves that the approach meets the real-time and high-accuracy requirements of master–slave mapping control for the Da Vinci surgical robots and other similar systems. In addition, the proposed approach can also serve as a design reference for other types of robotic arms that do not satisfy the Pieper principle.

Removal of pediatric stage IV neuroblastoma by robot-assisted laparoscopy: A case report and literature review.

Abstract: Removal of pediatric stage IV neuroblastoma by robot-assisted laparoscopy: A case report and literature review