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Copyright of Journal of Fuzhou University is the property of Journal of Fuzhou University, Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Machine Tool & Hydraulics is the property of Guangzhou Mechanical Engineering Research Institute (GMERI) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Computer Measurement & Control is the property of Magazine Agency of Computer Measurement & Control and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To improve the preoperative positioning efficiency and terminal operability of the minimally invasive surgical robot，a new multi-slave manipulator system of minimally invasive surgical robot is designed，which includes the preoperative positioning mechanism and the remote-center mechanism. Three surgical instrument arms and one endoscopic arm can be installed on the base. The fixed point of the end can be realized through the parallelogram mechanism in the remote-center mechanism，and the workspace can be increased by adding redundant DOF on the basis of the pitch，roll，and translation DOFs. To facilitate the doctor to adjust the height of the remote-center mechanism before the operation，the gravity compensation joint of the preoperative positioning mechanism is compensated for the gravity of the remote-center mechanism by the constant force spring. Based on the structural design of the multi-slave manipulator system，the forward kinematic analyses of the active part and the passive part are carried out. Since the preoperative positioning mechanism is used for preoperative positioning on the active part and each joint of the passive part will be locked during the operation，the inverse kinematics and the workspace of the active part are only analyzed. By comparing the motion trajectory simulated by SolidWorks with the motion trajectory of the end of the robot obtained by Matlab，the rationality of the structure of the multi-slave manipulator system and the correctness of the kinematics can be verified.

In order to improve the positioning accuracy and motion stability of endoscopy surgery robot with remote motion center (RCM) of slave manipulator，the equivalent centroid position of the component is obtained by dynamic equivalence of slave manipulator，and the gravity compensation of the manipulator is carried out by the pull spring-rope wheel. Then the dynamic model of RCM mechanism from the slave manipulator is established according to the Lagrange equation，and the gravity compensation is carried out by the method of calculating moment. By comparing and analyzing the motion response curves of each joint of the manipulator after gravity compensation with Adams，it shows that gravity compensation model can effectively compensate gravity items.

Copyright of Journal of Fuzhou University is the property of Journal of Fuzhou University, Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

At present,most robots need to consume a large amount of energy to overcome their own gravity during operation. In order to reduce energy consumption and improve robot performance,a gravity compensation mechanism（ GCM） for a rotating joint manipulator is proposed. A non-circular gear planetary gear and torsion spring are used in the device,the gravity compensation of arbitrarily reachable working space of the manipulator can be realized,the static balancing mechanical model of the manipulator is established,the non-circular gear planetary gear train is designed according to the static balance constraint condition,and the transmission ratio distribution of non-circular gear planetary gear train is discussed. The simplest gear train that satisfied the moment balance is obtained. The design and analysis of the 2R parallel four-bar mechanism manipulator is carried out and imported into ADAMS for verification. The simulation results show that the driving torque is effectively reduced.

By adopting a genetic algorithm for optimization of neural network,the gravity compensation for robot arm is researched.Firstly,through the basic knowledge of mechanics and D-H parameter to set up robot kinematics model,the theoretical computation formula of the gravity item of each joint torque in robot arm is got.Secondly,in the Solid Works simulation software,the simulation value of the gravity item in some certain pose got,thus the correctness of the theoretical computation formula is verified.Finally,the predicted value of the gravity item by genetic algorithm for optimization of neural network is obtained.Experimental results show that the predicted value of gravity items of robot arm learnt with this method is basically conforming with the theoretical value.Consequently,the work load of calculation for the gravity items of robot arm is effectively reduced.Furthermore,this method provide a possible way for the real-time control.

Copyright of Journal of Beijing University of Technology is the property of Journal of Beijing University of Technology, Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of China Mechanical Engineering is the property of Editorial Board of China Mechanical Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Harbin University of Science & Technology is the property of Journal of Harbin University of Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Acta Automatica Sinica is the property of Chinese Academy of Sciences, Institute of Automation and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)