Papers by Keyword: Micropositioning Table

Abstract: In order to improve the machining accuracy of the precision surface grinding machine, a 3-DOF micropositioning table is used as an auxiliary table to form the dual infeed system with nanometer level positioning accuracy. This paper mainly deals with the static characteristics of the micropositioning table. The direct and inverse kinematic models are obtained under different orientation descriptions, and the inherent relationship between different orientation descriptions is investigated. By use of Eular angle description, the reachable orientation space of the micro-positioning table is obtained. The theoretical static stiffness on the top surface of the table is also given, and the experimental tests are carried out to verify the established models.

Abstract: In order to realize active grinding control, a nanometer micropositioning table is designed. The table has a circular working area with diameter of 150 mm. Three piezoelectric actuators are utilized in parallel to drive the moving part with flexure guide mechanism. Through cooperation of the three piezoelectric actuators, the moving part can implement 3-DOF nanometer positioning. The flexure hinge mechanism can also provide preload for the actuators. The preload can keep the moving part from separation with the piezoelectric actuators during moving process. The dynamic model of the micropositioning table is developed with consideration of the driving circuit. To improve the dynamic performance of the micropositioning table, a decoupling PID controller is designed by use of frequency domain approach. The experimental tests have been carried out to verify the performance of the micropositioning table and the established decoupling controller.

Abstract: In order to compensate the force induced deformation of the precision grinding, a piezoelectrically driven micropositioning table is developed to actuate the workpiece for error compensation. To better understand the performance of the micropositioning table, the deformation patterns and stiffness distribution of the micropositioning table under normal grinding force are investigated by computational finite element analysis method. It is noted that the moving part of the micropositioning table can be considered as rigid body and the maximum static stiffness is located at the center of the top surface. The experimental tests are carried out to verify the analysis.

Abstract: In order to implement dynamic compensation for the wheel vibration of surface grinding machine, a micropositioning table with high stiffness and response frequency is designed. The micropositioning table is driven by three piezoelectric actuators with stiffness of 400 N/μm. Three capacitive sensors are utilized to form feedback control and flexure hinges are used to guide the moving part and preload for the piezoelectric actuators. The kinetics of the micropositioning table has been analyzed to understand the relationship of the control voltage and the posture of the moving part. Due to the coupling characteristic of the system, the decoupling control method is introduced to improve the performance of the table. Experimental tests are carried out to investigate the performance of the micropositioning table.

Abstract: In order to realize dynamic control during surface grinding, a 3-DOF (degree of freedom) micropositioning table driven by three piezoelectric actuators has been developed. The monolithic flexure hinge mechanism is utilized to provide preload for the piezoelectric actuators. The table has an outline dimension of Φ150×145 mm and a working range of 12 µm. The resolution of the table is less than 5 nm and the stiffness under open loop condition is approximately up to 94 N/µm. The design of the micropositioning table is presented with consideration to achieve the high dynamic characteristics. The dynamic models of the table have been established. Experimental tests have been carried out to verify the performance of the micropositioning table and the established models.