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Copyright of Journal of Computer Engineering & Applications is the property of Beijing Journal of Computer Engineering & Applications Journal Co Ltd. 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 South China University of Technology (Natural Science Edition) is the property of South China University of 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 Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural 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.)

Rope-driven super-redundant manipulator has the characteristics of strong flexibility and large working space, which can be employed for various aviation operations in space activities to replace astronauts. Based on the research background of spacecraft on-orbit maintenance, this paper simulated the corresponding experimental environment, and designed a RGB-D based mobile rope-driven super-redundant robotic arm positioning and grasping system. First, it improved Mask R-CNN algorithm to reduce the model size and ensure the detection accuracy. Then it input the image collected by Intel RealSense D435 i to the target detection model to obtain the target category and position information. Further it used the adaptive end position update algorithm to recursively calculate the forward and inverse kinematics model of the manipulator, and combined the trajectory planning to complete the three-dimensional space positioning and grasping of the target. The experimental results show that the improved Mas k R-CNN algorithm can effectively reduce the model size while ensuring accuracy. Moreover, the inverse kinematics of the grasping system is solved quickly with good positioning accuracy, and can effectively complete the aircraft grasp task. [ABSTRACT FROM AUTHOR]

In this paper, based on the linear inverted pendulum (LIP) model, the multi-walking of biped robot is analogous to the multi-swing of a three-dimensional inverted pendulum. In terms of the concept of 'divergent component of motion (DCM)', the dynamic equations expressed by using Center of Mass (COM) and DCM are studied. Two DCM closed-loop controllers are designed:one-step DCM terminal invariant disturbance rejection controller and real-time DCM trajectory tracking closed-loop controller. Both controllers can effectively suppress the disturbance, so that the DCM of the actual robot does not diverge, and which is used to plan the COM trajectory of the biped walking process. Based on the COM trajectory and biped end trajectory, the numerical method for solving inverse kinematics of biped robot is studied. The whole set of solving problems from input footprint to output joint angle in biped walking process is completed, and systematize the method of biped gait planning. Finally, combining with a ubiquitous robot model, all the algorithms in this paper are simulated via MATLAB platform. The simulation results verify the effectiveness of the method.

It is difficult to establish Jacobian matrix and determine the coordinate frames of links for non-standard actuator. A new analytical method to establish the Jacobian matrix and determine the coordinate frames for joints and links are proposed in this paper. The proposed method made the positioning analysis of end-effector easier in space. At the same time, it is necessary to prove the effectiveness of the proposed method theoretically and verify the localization and configuration capabilities through simulations. First of all, forward kinematics model was set up based on a non-standard five Degree Of Freedom (5-DOF) actuator. A frame transformation is performed from base coordinate to end-effector coordinate. The relation between two adjacent joints is defined by a homogenous pose matrix. Secondly, the necessary and sufficient conditions for comprehensive localization are derived. They can guide the actuator to perform various tasks, such as tracking, assembly and autonomous grasping. A 5-DOF actuator is considered here as an example and this holds good for any N-DOF. Thirdly, inverse kinematics solutions are obtained by using artificial Neural Network (NN) based on back-propagation Multi-Layer Perceptron (MLP, multilayer perceptron NN) and are not unique. A unique solution using nonlinear minimization optimization is found. A NN based on supervisory learning method including three inputs, twenty neurons and five outputs has been used. Excitation function tansigmoid and linear excitation function pureline are in hidden and outer layers respectively. In Cartesian coordinate space, NN is trained by means of Levenberg Marquardt (LM) algorithm. The training sets used are Denav Hartenberg (DH) parameters and Cartesian coordinates. The weights are updated continuously which reduces the Mean Square Error (MSE) gradually. When MSE reaches the threshold set up, NN training will be terminated. After training, the test sets are used to examine the capability of NN. Fourthly, there are two evaluation functions viz., localization and cost functions. The localization function is defined to evaluate the positioning property of end-effector. At the same time, in task space, it will check whether the actuator has reached the target point along the direction needed or not. The cost function is defined to evaluate the kinematics configuration. There is a great relevance between cost function and Jacobian matrix. Velocity mapping from each joint to the end-effector was described by Jacobian matrix. So the cost function could give expression for kinematic configuration. At the end, simulations and experiments are conducted. The settings include industrial computer UNO2184G, 5-DOF non-standard actuator, Windows 7, MATLAB2012a. Coordinate frames for each joint are established and D-H parameters are determined. Then relative pose matrix is obtained between each of the two adjacent joints. Initial end-effector pose is obtained following right multiplication rule. The end-effector space range is formed under each joint operation range. Then, simulation is performed using NN, obtained localization and cost functions. The following results are obtained. The rank of Jacobian matrix is equal to 5. Therefore, this actuator met necessary and sufficient conditions for comprehensive positioning. NN method for solving inverse kinematics has reduced the computational complexity compared to conventional method. There are 21 groups of solutions when positioning to (41.4, 89.0, 104.5). The optimal solution obtained is (21.61, 91.44, 135.52, 221.42, 0) according to localization function rule. The optimal solution obtained according to cost function rule is (21.61, 125.73, 108.42, 221.99.41, 0). NN accuracy is 89.9% (approximately) while conventional method is 87.5%. By approximate estimation, the errors for θ1, θ2, θ3, θ4 and θ5 are 3.7°, 3.1°, 3.5°, 3.3°and 4.5°respectively. NN used 1. 2 seconds while conventional method completed in 0.9 seconds. Therefore, computation accuracy has improved by 20% and efficiency by 2.4%. If the system is linear, the conventional method is chosen when less demand in real-time. In contrast, if the system is nonlinear, new method proposed in this paper is chosen when more demand in real-time. The minimum value of localization function is 0.96. The maximum value of cost function is 4.0349×1014. These two parameters decide the comprehensive positioning and the kinematics configuration. From the results presented, it can be concluded that the non-standard actuator with MLP has better localization and optimal configuration. [ABSTRACT FROM AUTHOR]

In this paper, an inverse kinematics issue of robot was studied based on the properties of Jacobi matrices. Especially, the cases with the redundancy and singularity of the matrix were investigated. Firstly, a method was proposed to solve the inverse kinematics. Then its applications were presented. Finally, some simulation experiments were carried out. The results provide a basic method for the programming and control of robot action. [ABSTRACT FROM AUTHOR]

In this paper, the model of a self-designed 6-DOF manipulator was established by utilizing standard DH ( Denavit-Hartenberg) rules, and the kinematics solutions were obtained. For the inverse kinematics, according to the structural characteristic that the first three joint axes are intersected at one point, the arm was decoupled into first three and last three joint variables based on an inverse decoupling mechanism. Then the complete 8 analytic solutions were obtained when the arm was under nonsingular configuration. In the process of computing forward and inverse kinematics solutions, intermediate variables were used to substitute homogeneous matrices multiplication to reduce the running time. Finally, computer simulations were carried out for the kinematics algorithms and workspace, the results verify the effectiveness of algorithms and the feasibility of this mechanical structure, and provide prerequisite for the manipulator motion planning and real-time control. [ABSTRACT FROM AUTHOR]

In order to meet the demand of large space automation production. An innovative concept of industrial robots which processed large workpieces (such as wing riveting) in large work space was presented. The paper also put forward whole configuration and branched chain configuration of 8-UPS parallel robot. Craftily configurations of branched chain's single degree of freedom kinetic pair ensure the robot's walking function. Based on the inverse kinematics model, the changing situation affected by driven bar length was solved. Based on three dimensional search method, MATLAB was used to solve the workspace of parallel mechanism in processing conditions, and based on the adaptability of the height of the processing objects, the workspace influenced by parallel mechanism bar length was analyzed. The study found that the cross-sectional area of the workspace of the z axis increases first and then decreases. Gradually, the empty part disappears.When z = 2 700 mm, the cross-sectional area reaches the maximum value of the mobile platform workspace. With increase of the length of the minimum rod, the center of rotation in the range of vertical space increases gradually, so we can guarantee sufficient workspace for parallel robot. [ABSTRACT FROM AUTHOR]