Research On Ultra-precision Work Table Of 2-DOF And Its Control System

Precision positioning technology, which plays a very important role and has good application prospect in the sophisticated industrial production and scientific research, is one of the key technologies in modern science fields. Hence, on the basis of designing the mechanism of a 2-DOF micro-displacement precision work table and analyzing its kinematic and dynamic performance , the driving control system for this work table is developed and the integrated experimental platform is realized, by means of adopting distributed architecture and the design thought of modularization, applying DSP and FPGA as its central control unit and PA85 as power amplify unit and combining with the latest research achievements of control technology.The contens of this dissertation as below:Chapter 1: The background and significance of the research on precision positioning technology is discussed, the current research situation and development trend are expatiated, the essentiality of research on 2-DOF precision work table is illustrated, the research content of this dissertation is presented and each chapter of this dissertation is arranged.Chapter 2: A 2-DOF micro-displacement precision work table is designed and its basis structure and working principle is introduced, the kinematics and dynamics of this work table are analyzed, and finite element analysis is used to validate the feasibility of above design.Chapter 3: The hysteresis nonlinearity mechanism of the piezoelectric ceramic actuator is analyzed, the Preisach model is chosen to model the hysteresis character of the PZT actuator after comparing the features of all different hysteresis models, and then neural network and support vector machine (SVM) are respectively used to solve the problem of function approximation, in order to characterize the hysteresis nonlinearity of the PZT actuator.A conclusion is got that the Preisach model based on SVM is much more effective and excellent through comparing the experimental results with the theoretical analysis results.Chapter 4: A digital driving control system of 2-DOF precision work table, applying DSP and FPGA as its central control unit and PA85 as power amplify unit, is developed. Each function module is analyzed in detail and experience is summarized in the process of the design and debug, thus an integrated experimental platform is accomplished.Chapter 5: After establishing the transfer function of whole closed-loop system, four control methods including the open-loop positioning control method based on feed forward model, semi-closed loop control method respectively based on traditional PID, Genetic Algorithms tuning PID and fuzzy PID are detailedly analyzed, furthermore, the experimental platform developed before is used to study on precision positioning and tracking curve path in plane. Thus the superiority of the controller is validated by comparing and analysing the experimental results and the optimum control algorithm is got.Chapters 6: The main conclusions of this dissertation are presented and its related research prospect is put forward.