Papers by Keyword: Kinematics

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Authors: De Zheng Song, Chao Yun, Dong Zhang, Ming Fan
Abstract: For the problems that the dexterity of movement was not enough, the grinding path was uncontinuous as well as the accuracy and efficiency were influenced while the gripper needed replacing, when complex curved workpiece was under grinding by six freedom degrees grinding robot, a new type redundant grinding robot, PPPRRRR, was proposed. A new type robot system coordinate and kinematics model of robot space were founded by the homogeneous transformation. Robot kinematics equations were derived. By ADAMS, the work space of robot was obtained. The relative position of the grinding contact wheel and robot was optimized by orthogonal test method. It lay the foundation for in-depth study of this type of grinding robot.
535
Authors: Zeng Ming Li, Bin Bin Peng, Bao Gang Yang, Hao Yuan Chen
Abstract: In the paper, a novel 2-DOF (degree of freedom) plane translational parallel manipulator with passive universal joints and three legs is presented. Firstly, the 2-DOF translational parallel manipulator which has the spatial structure and high bearing capacity in the direction perpendicular to the kinematics plane is described. Then, the kinematics analysis of the 2-DOF parallel manipulator, which include inverse and forward solutions, are studied in detail, and the Jacobian matrix of the parallel manipulator is also derived based on it. Lastly, to improve the stability and bearing capacity further, the symmetric mechanisms with four legs and passive universal joints are constructed by adding a leg in parallel. The proposed 2-DOF parallel manipulator not only has the simple structure, but high stiffness especially in the direction perpendicular to kinematics plane for its spatial arrangment and passive universal joints.
541
Authors: Tian Yu Li, Ding Xuan Zhao, Fang Yuan Han, Zhong Ke Shi, Meng Wang, Guo Ping Huang
Abstract: Parasitic motion of 3-PRS (prismatic-revolute–spherical) parallel mechanism is discussed, inverse kinematics model of this mechanism is established. Based on the structure feature of 3-PRS parallel mechanism, a new forward kinematics algorithm for this mechanism is presented. The algorithm consists of approximate calculation and iterative calculation. The mathematical model of the proposed algorithm is clear simple, no derivative operation or Jacobi matrix inverse operation is needed, so computation is less. The experiment shows that in the same computing environment, the calculation speed of the proposed algorithm is about 2 times of the existing algorithms to achieve the same accuracy, so it can be applied to real-time control. Complexity and workload of programming is less than half of before. The algorithm is based on 3-PRS parallel mechanism, but it is also applicable for other parallel mechanism.
303
Authors: Wen Jia Chen, Yan Zhong He, Jiang Zhang
Abstract: In the past decades, a number of parallel manipulators have been extensively studied. However, most efforts are dedicated to six degrees of freedom (DOF) or three-DOF manipulators. There is a need for equipment providing more than three DOF's arranged in parallel and based on simpler arrangements than six-DOF arrangements in application. This paper presents a novel four-DOF parallel platform manipulator with base mounted prismatic actuators. The manipulator is driven by four linear actuators. The movable platform of the manipulator can translate along two directions and rotate around two axes respectively. The kinematics model is formulated, which describes the inverse and forward kinematics transformation. It is very easy to develop a five-axis NC machine-tool which is of large-workspace based on the four-DOF parallel mechanism presented in this paper.
2168
Authors: Ionel Conduraru, Ioan Doroftei, Alina Conduraru Slatineanu
Abstract: Mobile robots applications are demanding them to move in tight areas, to avoid obstacles, finding their way to the next location. In the case of wheeled robots, these abilities mainly depend on the wheels design. A mobile robot with omni-directional capabilities is very attractive because it guarantees a very good mobility in such cases, being able to move instantaneously in any direction from any configuration. These capabilities mainly depend on the wheels design. This paper provides some information about the mechanical design of an omni-directional mobile robot with modified Mecanum wheel, as well as about its control.
775
Authors: Zhen Zhang, Ya Fei Cao, Yan An Zhang, Hong Shang
Abstract: In the paper, a multisection snake-like manipulator named SnakeHelper is described. For rescue task, the manipulator is designed with cable driven and rear actuators. First, the mechanism design is presented. The manipulator consists of rear actuators, links, joints and cables. Then, some considerations on mechanism design of the device are given. The moment of the motor is calculated. The rotatory angle of each joint is also given against design parameters. At last, the kinematics analysis of the manipulator by D-H method is given.
563
Authors: Wen Jia Chen, Lan Lei Zhao
Abstract: Though computer technology has brought about virtual manufacturing to expedite design and analysis through simulation and visualization, machines remain essential, as ultimately products need to be made. There is a need for equipment providing more than three degrees of freedom (DOF) arranged in parallel and based on simpler arrangements than 6-DOF arrangements in application. This paper presents a new 4-DOF hybrid parallel platform manipulator with fixed-leg lengths and base mounted prismatic actuators. The movable platform of the manipulator can translate along two directions and rotate around two axes respectively (2T-2R). The kinematics model is formulated, which describes the inverse and forward kinematics transformation. It is very easy to develop a 5-axis NC machine-tool which is of large-workspace based on the 2T-2R, 4-DOF parallel mechanism presented in this paper.
1743
Authors: Alireza Akbarzadeh, Jalil Safehian, Javad Safehian
Abstract: In this paper, for the first time, kinematics modelling of snake robot travelling with concertina locomotion is presented. Next a novel kinematics modelling method is presented which has an advantage of allowing natural snake like locomotion. During concertina motion, certain parts of the body contract, expand or do not change their shape. This results into having different body curves for different parts of a snake. To simulate this, first we introduce a mathematical equation, called dynamic function, in which by varying a certain function parameter, body curve during motion is realized. To obtain concertina gait, the snake body is divided into three different modules, head module, tail module and main body module that connects the head to the tail module. Each module forms a specific curve which can be modelled using the proposed dynamic function. At each moment during snake locomotion, the kinematics of different links can be derived by fitting links to the body curve. Finally concertina locomotion is simulated using Webots software. Results indicate concertina locomotion can be obtained. Furthermore, the proposed dynamic function requires relatively lower computation requirement. Therefore, adaption of body curve to other real snake like gaits as well as mixed type locomotion is made possible. This works represents a first approach to a simulation of a snake-like mechanism in order to get basic characteristics of such locomotion and to enable our future research.
2786
Authors: Nicolae Joni
Abstract: Starting from the analysis of the modern robotic arc welding system from the kinematic point of view, the paper presents an original concept of the systems structure. Instead a combination of two open chains, as it is generally seen, the author proposes one single closed kinematic chain. The main element of this chain is the electric arc employed for welding, virtually seen as a vector which connects the two open chains, the robot and the part manipulator. This new approach could possibly change and simplify the way arc welding robots are programmed today.
429
Authors: B.F. Feng, Hong Shi, Guang Qi Cai
Abstract: Kinematics, workspace, dynamics behavior of a 3-DOF 3-Legged parallel robot with horizontal slide 3-link for steel snagging, which was developed by Northeastern University, are introduced. The steel spot snagging experiments have also been carried out. The wheel selection, removal rate, grinding power and their influence factors are studied. Comparing with hanging grinders used in most steel mills of our country, this robotic grinder can reduce labor intensity of workers, raise efficiency and guarantee quality greatly.
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