Two Dimensional Positioning Stage And The Decoupling Strategy

With the development of modern technology and industry, recent years have witnessed imperious demands on motion stage with long range and high positioning accuracy in the fields of Bio-mechanical, Military Engineering, Precision Optical Engineering and Precision Mechanical Engineering. Macro/micro dual drive technology is an effective strategy in realizing long rang as well as high precision positioning. With the combination of macro and micro drive, the system can achieve high precision positioning under premise of long range motion. Thus carrying out research on key technology in the field has a great and far-reaching significance.Based on the above-mentioned background and significance, this thesis builds a2-D macro/micro dual drive long-rang high precision positioning stage:the liner motor fulfils long range motion, high precision grating ruler measures its real displacement, and flexure-hinge based micro positioning stage will compensate this error, to improve positioning precision.In the first chapter, the background and significance of macro/micro dual drive technology was introduced. Then, the research status of decoupling micro positioning stages and the decoupling strategy between macro and micro stages are stated.In the second chapter, overall design scheme of micro stage was proposed, and parameter calculation, simulation and analysis of the system’s stiffness, frequency, displacement amplification, and coupling degree were conducted. A2-D micro positioning stage with large displacement amplification and low coupling degree was designed and machined through wire-electrode cutting method.In the third chapter, the micro drive positioning stage system was built and its open-loop performance was tested and analyzed. Then theoretical model was established through system identification, and initial PID controller was designed. Closed-loop PID control experiment was conducted and its linearity, resolution and coupling degree were measured.In the fourth chapter, positioning performance of liner motor stage was assessed and multipoint positioning control flow was proposed with the consideration of micro stage’s motion range. The multipoint positioning and decoupling experiments of macro/micro dual drive stage were conducted, and it confirms that with the adoption of improved macro/micro control flow and double semi-closed-loop control strategy, the whole system can achieve high precision, low coupling and long range positioning.In the fifth chapter, the research work was summarized and suggestions were raised.