| Joints, as the most basic structure of the robot composition, have a crucial impact on the output performance and application of robot. In recent years, with the development of science and technology, robot's technology has been continuously improved and the application of robots has also been greatly promoted to many fields.Redundant and dual-arm manipulators have been rapidly developed in recent years.Compared with the non-redundant manipulator, the redundant manipulator has been greatly improved in the aspects of motion space, flexibility, operability and space obstacle avoidance ability, etc. In addition, the dual-arm manipulator has been used to replace human in many areas due to its strong collaborative operation capability like the two arms of human. At present, most of the researches for these manipulators have been focused on the trajectory planning, dynamics and dual-arm coordination;however, the research for the mechanical structure of the manipulator is insufficient.After several decades of development, the mechanical structure of the manipulators is usually composed of joints with single-DOF such as rotaty joint or linear motion joint.In this case, during the movement, only part of the drives is being used for efficient output, which results in a lower overall power density of the manipulator and the output capacity of the robotic arm is usually limited by the weakest link. Although researchers have increasingly raised a variety of algorithms to improve the performance of the robot, including the implementation of speed, operational accuracy,intelligence and stability; however, the fundamental issues have not been solved very well.Surrounding the mechanical design and verification of the multi-DOF joint, a new bionic joint based on mechanism with double-inclined planes was proposed in this dissertation. Based on this joint design, a redundant manipulator and a dual-arm manipulator were developed aiming at breaking some of the limitations of the existing manipulators from the mechanical structure. The novel joint structure is a multi-kinematics hybird structure. This new joint can realize two-DOF motion including yaw and pitch, and they are realized by two drivers; in this case, the compactness and output capacity of the joint can be greatly improved. The presented redundant robotic arm consisted of three joints of this type and a general single-DOF rotary joint. In addition, a dual-arm manipulator based on two of this redundant manipulator was presented. In this dissertation, the motion principle and mechanical design of the proposed joint, the kinematics and dynamics analyses, the simulation and experimental work were carried out; the kinematic and dynamic modeling and solving, trajectory planning and motion control of the redundant manipulator were carried out; a position/specification action library based strategy for dual-arm coordination were proposed. The main contents and achievements are presented as following:(1) The motion principle, mechanical design and optimization of the proposed joint.We analyzed and summarized the research work of various joints, especially the multi-DOF joints. Through comparing the structure features and performance of these joints, we proposed a joint structure based on U-joint (universal joint) and cylinder pairs with inclined plane. Five versions of the joint were designed and analyzed, and the output difference of these five joints in terms of the built-in and external configurations of the U-joint was analyzed. Then the structure was optimized according to the results. The influence caused by the variable of the inclined planes of the cylinder pairs on the output of the joint was analyzed. The results provided a variety of options with different input and ouput ability. By comparing the output ability of the joint under two kinds of driving modes: driven by servo motor with gear reducer and the direct drive by motor without the reducer, we chose the former in the latest version.(2) Kinematic and dynamic modeling and solving for the proposed joint. For the coupling characteristic of the joint, a kinematic decoupling method based on D-H method was proposed to solve its positive and negative solutions. The dynamic model of the joint was simplified by Lagrangian method. Then by using Adams and MATLAB Simulink software, the dynamic response characteristics of the joint were presented.(3) Simulation analysis and experiment for the proposed joint. Through the simulation analysis, under the same output conditions, the input requirement of the new joint and the general two-DOF joint (composed of two rotaty joints with single-DOF)is obtained. The proposed joint can save nearly 2/3 of the motor torque and the power, that is, the proposed joint can get a higher output ability under the same input conditions. And two sets of experimental platform were built for the joint,one can realize the transformation of motion from 3D joint space to 2D plane, and the other using 3D motion capture system to capture the joint 3D space motion directly. The experimental results focused on the trajectory tracking of the sine wave, linear swings and circulars motion. The experimental results were high coincidently with the simulation, and the kinematics solutions and control schemes were verified. Errors were analyzed for further joint mechanism optimization.(4) Modeling and principle verification of redundant and dual-arm manipulators. A new type of redundant and dual-arm manipulators robot based on this joint were proposed, which combines the proposed joint and the rotary joint with single-DOF. Their kinematics and dynamics were modeled and solved, and the motion planning and control scheme were also proposed. The redundant manipulator test platform was built and the linear and circular trajectories tracking simulations and experiments were carried out. Then a position/specification action library based strategy were proposed for dual-arm coordination. The strategy was verified by using UR (Universal Robots) robot through grabing, moving and assembly experiments. A new design concept was proposed from this dissertation... |
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