A Novel Handheld Bimanual Surgical Robot for Single-Port Laparoscopic Surgery


 Background: single-port laparoscopic surgery is a hotspot of minimally invasive surgery, but its promotion is limited because of operational triangulation and instrument conflict. Robot technologies can cleverly solve this dilemma. But most of the surgery robots need high cost and long time to setup and mainly for complex surgery currently. There is no portable single-port laparoscopic robotic surgical instruments suitable for simple abdominal surgery. Method: This paper presents a handheld single-port laparoscopic surgical robot. It consists of two manipulate arms, both of the arms have 2 degrees of freedom, and two more degrees of freedom can be applied by handheld. The left arm has the function of pulling tissue, while the right arm is equipped with a laser fiber, which can be used for tissue cutting and hemostasis with a 980nm diode laser. Kinematics analysis, dynamic simulation, modal analysis and vitro simulation experiments were conducted to verify the feasibility for the handheld single-port laparoscopic robot. Result: The bimanual surgical robot can provide enough workspace, the gripper and laser head have stable working ability, and can successfully complete the fenestration and drainage of hepatic cyst. Conclusion: This bimanual surgical robot has the potential to become a surgical instrument for simple intraperitoneal surgery. It can provide a small, portable and inexpensive surgical robot system.

for Da Vinci is more than 1 hour and laparoscopic surgery is more cost effective than it 76 in cost analysis with an economic model (21), The longer of the setup and takedown, 77 the longer the patient will have to undergo general anesthesia. those disadvantages 78 making them difficult to promote in primary hospitals. So, the current RASPLS is not 79 apply to everyone who needs surgery, especially the poor and the surgery is less 80 complicated.

81
Hepatic cyst is a common benign disease of the liver. Some patients with the 82 increasing of cyst or oppression surrounding tissue can appear some symptoms, 83 including abdominal pain, bloating, liver enlargement, abdominal mass, nausea, 84 vomiting, and loss of appetite. More serious can appear ascites, edema, jaundice, 85 hemorrhagic hepatic cyst and other symptoms(22-24). Today, laparoscopic with two or 86 three ports has been widely used in fenestration and drainage of hepatic cyst(24). We 87 should also pursue a single port laparoscopic to this procedure. But, using the da Vinci® 88 8 Surgical System is too expensive to extended to everyone. 89 So, we need portable surgery robots that cheap and easy to setup and operate. In 90 this paper, wo present a microsurgical robot for laparoscopic surgery. The device that 91 mounted a 980-nm diode laser(25) on the right arm for incising can be used to operate 92 fenestration and drainage of hepatic cyst under a magnetically anchored camera(26), 93 The feasibility of the equipment was verified through kinematics analysis, dynamic 94 simulation and simulated vitro experiment.  The bimanual robot has four degrees of freedom, namely three degrees of rotation 103 and one degree of movement. In this paper, D-H method is adopted to establish the  (Table 1), θ-joint Angle, d-link offset, 106 a-link length and α-twist Angle. The two degrees of freedom, θ 1 and d, are 107 generated by the hand. Other two DOF ,θ2 andθ3, are generated by the robot itself.
With D-H method, use a 4x4 homogeneous transformation matrix to describe the 113 spatial relationship between two connecting rods, and allow the coordinate system {i} 114 to be coincident with the coordinate system {i-1} through rotation and translation.

115
Therefore, the coordinate transformation matrix of the coordinate system {i} in the 116 coordinate system {i-1} is: According to the above method and the relevant data in Table 1, it is possible to 119 establish the equivalent homogeneous transformation matrix of the coordinate system 120 of the end tool (grippers or laser head) relative to the base coordinate system in turn, so 121 as to establish the kinematic equation of the bimanual robot. The orientation matrix of 122 the execution end in the base coordinate system is(q1 represents θ1, and so on):   The gripper is mainly used to drive the slide by the motor to make a linear motion 141 in the shell, which is finally converted into the stripping action of the actuator end of 142 the rod-mechanism. Obtain the stripping force of the stripper through dynamic 143 simulation analysis, as well as the speed and acceleration curve of the working process. Based on the above calculation results, import the model into the UG 155 simulation module (Fig.3), and establish the dynamic simulation model of the 156 13 stripper (Fig.3a). the speed and force of gripper changing smoothly in dynamic 157 simulation (Fig.3b, c). For the ease of calculation, it is assumed that each joint position is fixed through 195 is rigid connection. See Table 2 for the first six-order modal frequencies of the left arm.  In order to represent the vibration characteristics of the left bimanual robot at a  Table 2 shall not appear in the operation, so the structural resonance will not occur. The  We conduct the vitro simulation experiment of the bimanual robot in a laboratory 215 platform for fenestration and drainage of hepatic cyst (Fig.6).    it is easy to cause electric burning, burns and fire hazards (46). But, those drawbacks 296 will not occur in laser knife because of the non-contact way and its physical 297 characteristics.

298
However, the strength of the robot is not enough to operate other procedure, further 299 research would need to be made by improving the structure designation(47). Future 300 23 works will focus on improving system accuracy and more driving force. In addition, 301 we also need to improve the robotics arm execute speed to ensure that the robot can 302 efficiently complete the precise operation during the surgery. At the same time, for the 303 convenience and practical use of surgeons, a good interactive system should be 304 designed, and finally a robot can be operated by one physician. While much work 305 remains to be done, the bimanual robot still achieved the specific design goals. We 306 expect more advanced surgical tasks with in vivo animal models will be performed in 307 the near future.  The bimanual robot consists of two arms (Fig.7). The left arm consists of three  In addition, as the sleeve moving, the connecting rod is pulled through the lower and 335 middle axis to move, which causes the gripper to create a grasping and opening motion