Study On Five-DOF Lettering Robot System

Robotics is an important branch in hi-tech research nowadays, which is taken seriously generally by governments. After60years of development, robots have become an essential unit in the industrial automation production line and the flexible manufacture systems.In this paper, we design and manufacture a five-dof lettering robot aimed to mark characters on steel surface. By taking this five-dof serial robot as research object, further study on robot mechanical structure, forward kinematics,inverse kinematics, workspace, velocity Jacobian matrix, dynamics and trajectory planning problems has been done and a detailed theoretical analysis to solve the problem that how to write characters on space plane, cylindrical and spherical surface are performed.The thesis is divided into seven chapters.Each chapter is summarized as follows:In the first chapter, firstly analy the current situation and prospect of industrial robot at home and abroad. Then introduce the present state and trend of development of robot kinematics, workspace and trajectory planning. At last the research purpos, content and sibnificance have been described briefly.In chapter Ⅱ, analy the robot structure in detail and design and manufacture a5R robot which meets the Pieper Geometry standards in structure. Build the3D model using Solid Works software, and then put forward reasonable suggestions for the improvement of the experimental prototype.In chapter Ⅲ, coordinate system of links is established by using D-H method, then the equations of kinematic and inverse kinematics are derived. We use comparison method to choose the most suitable inverse solutions. While deriving speed Jacobian matrix of lettering robot subsequently,geometric and numerical methods have been used to achieve the size of the robot’s workspace. We have also analyzed the influence of link length and the joints’installation manner on the workspace size. Lagrange method is exploited to obtain the dynamics equations of the letterring robot with five degree of freedom. Then structural parameters of litterring robot are substituted into the equations to analy the influence of characteristics of gravitational, interia, Coriolis forec and centrifugal force moment to joint torque.In Chapter Ⅳ of the paper, a further study on robot space linear and circular interpolation based on the timing interpolation algorithm in Cartesian coordinates has been made. The interpolation includes position interpolation and orientation interpolation. S shape Acceleration-Deceleration algorithm is adopted in trajectory planning of robot to reduce concussion.In Chapter Ⅴ, a detailed theoretical analysis on solving the problem that how to write characters on space plane, cylindrical and spherical has been made. We can obtain the pos matrix of penpoint coordinates through writing characters on plan, cylindrical and spherial by projection. In addition, there is distortion when characters are projected to plan and cylindrical distortion surface, except spherical surface.In chapter Ⅵ, the structure of the open control system has been discussed firstly.Then the controling system of this lettering robot is built up by PC and Googol’s motion control card. Some of motion control programs and interfaces have been written by VB, which realising the basic motion controling of the lettering robot. Finally, briefly described the process of establishing the single line font and writing process, and then have done the writing experiments.In chapter Ⅶ,summarize the main research achievements of the thesis and look forward the follow-up research afterwards.