Research On Trajectory Planning And Motion Control Of Five-DOF Cutting Robot

With our market of manufacturing industry changing rapidly and greatly, the products need to be upgraded, it has become focus of the automatic processing industry to develop automation equipments which have high production applicability and can trial-manufacture samples fast. As the model product of automatic industry, industrial robot has the characteristics of dexterity of action, cramped construction and versatility, and been used everywhere in automatic production such as cutting, welding, assembling, spraying, packing, etc.. This article is written with the background of the rapid development of shipbuilding and ocean engineering, and sharp increasing of steel structure cutting quantity, produces a 5-DOF cutting robot, include the robot's mechanical body structure, the constructing of operating system, the study of kinematics and trajectory planning algorithm, so as to ensure that the robot can accomplish the cutting of various kinds of panels, tubes, Non-circular surface, intersections with a surface groove, etc..Firstly, this article introduces the structure of the 5-DOF cutting robot, making a kinematics model of the robot with modified D-H method, and solving kinematics inverse using inverse transformation method. As to the question of multiple solutions of inverse solutions, the writer uses flexible standard to select the solution. Then analyzes some examples which show that the optimized joint angle curves obtained by flexible standard are gentle, they have no angle mutations and the total movement angles are less. In order to observe the movement of the robot, the writer also established a combined simulator system of Matlab and RecurDyn.Then this article analyzes the stances of cutting curves, using Frenet coordinate system to describe the various kinds of cutting stances, the Frenet coordinate system is changing with different point positions of curves, it is an active coordinate system which is easier to describe local curve characteristics of the different points. For the cutting requirements of constant speed and variable speed, this article raised the plan of controlling speed path and interpolation algorithm. Finally, through the following of intersected curve, the writer conducts a simulation, the result shows that: the robot can accurately keep the expected position while following the track of curves, and the following accuracy and the robot's tip speed can meet the expected requirements.Finally, the writer establishes a robot hardware control platform with the PC and PMAC motion control card as the core, and then achieves servo control of the robot's joints. With Visual C++6.0 and Windows operating system as software platform, the writer develops a upper computer controlling software which has the functions of teaching and playback controlling and automatic programming. The online debugging of the 5-DOF robot shows that: the kinematics algorithm and the trajectory planning algorithm are correct. The upper computer can accurately control the robot to follow the track of different parametric curves as required, and the velocity perturbation and trajectory errors can meet requirements.