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This paper proposes a new effective kinematics method based on the dynamic visual window (DVW) for a surgical robot that is equipped with two instrument arms and one laparoscope arm, to enable doctors to achieve operations with their visual habits under the laparoscopic visual environment. The problem of the consistency principle between the doctor's operations under the visual window's feedback and the master-slave operations of the surgical robot is solved. The kinematics models of the surgical robotic arms are established, and the new kinematics methods based on the DVW of the laparoscope and instrument arms are proposed according to their inverse kinematics with respect to the visual coordinate system. Finally, the proposed kinematics method is verified by simulation experiments based on the theoretical algorithm and the mechanism model; the multiple sets of the simulation data are presented to illustrate the correctness and feasibility of the new method in this research.

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Background: Open surgical consoles widely employed in minimally invasive surgery have better ergonomics than closed consoles. To enhance surgical robots' ergonomics, operational efficiency, and safety, an effective master-slave motion alignment model should be established.Methods: The kinematic model of the robot system based on laparoscopic camera coordinate system is built in the first place. Then, the relative pose between the operator's eyes and the display is measured by Tobii Eye Tracking Sensor and is subsequently used to improve the master-slave motion alignment model. Results: Robot threading experiments are conducted by two doctors and three testers to verify the kinematic model. As a result, in contrast to the original model, the improved model reduces both operation time and the number of collisions.Conclusions: The improved master-slave motion alignment model, in which the transformation matrix between the operator's eyes and the display is employed, raises the ergonomics, operational efficiency, and safety.

Purpose – The characteristic of static is quite important especially for the manipulator with force feedback. This paper aims to improve the traditional static model by considering the limitations such as lacking of versatility and ignoring gravity of links. For this purpose, a new asymmetric mass distribution method on the analysis of universal “force-sensing” model has been put forward to overcome the limitations. Design/methodology/approach – Through the forces and torques analysis of every link and the moving platform, the static model of 3-RUU manipulator is acquired. Then, based on the physical meaning analysis of every part in the static model of 3-RUU manipulator, a new asymmetric mass distribution method on the analysis of universal “force-sensing” model can be obtained. Findings – The correctness of the static model of 3-RUU manipulator is verified by simulation results based on Pro/Engineer software and Adams software. Furthermore, experiment results based on a manipulator similar to the Omega.3 manipulator indicate that the universal “force-sensing” model can be applicable to the above manipulator. Originality/value – A new asymmetric mass distribution method on the analysis of universal static mathematical model has been put forward. Based on physical meaning of the above method, the “force-sensing” model can be established quickly and it owns versatility, which can be applicable to the 3-RUU manipulator, the Omega.3 parallel manipulator and other similar manipulators with force feedback. In addition, it can improve the accuracy of the “force-sensing” model to a great extent.