Research On Control Law Of3-DOF Parallel Platform

3-DOF (Degree of freedom) platform can achieve movement of three degrees of freedom,it can simulate the movements of aircraft, ships, cars, and tanks and some other objects’effectively, it plays a very important role in the study of flight simulator, ship simulator andcar simulator. In view of the function, features and application prospect in national defense of3-DOF platform, it become the focus of research without doubt. In this paper, the structure,the movement, control strategy and law of the3-DOF platform were studied through oftheoretical and simulation.A kind of3-DOF platform of special structure was introduced, the platform can simulatethe motion of rolling, pitching and heaving. The platform can eliminate the additionaltranslation movement.This paper analyzed the space structure of the platform, it got degree offreedom of the mechanism, created the kinematics model and got the solution of the forwardand inverse position equations. The servo electric cylinder was selected as driving device ofthe platform.It not only used mechanic dynamic analysis software ADAMS to build a virtualprototype of the3-DOF platform, verify the freedom and the accuracy of virtual model, butalso used ADAMS to simulate the movement of platform and get the characteristic curve. Thesignificance of ADAMS used in the research of platform have been proved efficient, itprovided the theoretic foundation and main parameters for getting the suitable parallelstructure platform. It reduced the dependence on physical model greatly.The research of control methods and strategy was the most important part of study ofplatform. The control strategy used in this paper is based on the kinematics model of theparallel structure, we just only study on the arbitrary single branch because each branch arethe same. After given the target position and attitude parameters, we can get the targetposition movement parameters of each servo electric cylinder, then put the target movementsignal to controller and then passed to the servo electric cylinder, thus achieved closed-loopposition control that all branch are independent with each other. The controller got by thisway is easy to debug, and its structure is very simple, so it was used in practical engineeringwidely. If you want to get better control precision, you should ensure the precision of positionof every close loop.This article describes two methods for simulation of the turntable control system, onemethod is using SIMULINK to build control system, and the other way is combined simulation make use of ADAMS and Matlab, Through the simulation can observe the effectmore intuitively. In addition to classical control methods, intelligent control methods andmorden control theory were introduced. Using the disturbance observer can remove the effectof interference signal.