The Background Research For 4-DOF Lettering Robot

Robotics is an important field in researching high technology,and is paid attention to by governments. In company with development of robot's application in extent and depth,the background research before robot is industrialized must be do. The paper deeply studies the principal problems of kinematics system,for example forward kinematics,inverse kinematics,workspace and trajectory planning,basis of robotics and illustrating the 4-DOF lettering robot design by us. The dissertation is divided to six chapters: 1. The present state and trend of development of kinematics,workspace and trajectory planning are proposed at first,and then the goals and contents of this dissertation have been put forward briefly. 2. Founded on the summary of the driver of robot-joint,the new joints designed by us are improved on in aspects of conFig.uration and technique,at the same time machining technique of some special parts is arranged,and an articulated robots is assembled with two of the joints. 3. D-H coordinate systems of the robot are set up,and the transformation matrixes of near two links are improved on to make D-H method more general. Afterward a series of kinematics equations are deduced to realize kinematics forward solution by means of transformation equations. It is comparatively complicated to analyze inverse kinematics,and there is not a solution in common yet,because it is a problem to solve no-linear equation in face. This dissertation solves inverse kinematics using algebra method,and program to confirm improved D-H method in the software—matlab. 4. Volume index,singular position and dexterity indices of the workspace reflects different aspects of positions and postures. The paper determines axial cross section of volume index of workspace in illustration,and determines dexterity indices using a new means basing on theories of rotation transformation and extremum,finally analyses the influence of link length. 5. Robot's trajectory planning is very important in the control of robotics. Based on demands and restrictions of trajectory planning,this paper puts forward to a novel method of trajectory planning. The method is that the control points are obtained by interpolation calculation of three order polynomial in joint space,after via points in Cartesian space are found with finite error method,the points are mapped to the joint space by inverse kinematics. This method is real-time and accurate by virtue of synthesizing the advantages of both the path planning in joint space and that in Cartesian space. 6. Some conclusion are given in the sixth chapter,The main innovative achievements of the dissertation are summed up.