A macro-micro composite precision positioning stage is mainly used in microelectronics manufacturing to achieve high-velocity and high-precision positioning. The residual vibration caused by high-speed macromotion will prolong the settling time and influence the working efficiency. This paper proposes a rapid dynamic positioning (RDP) method to quickly reduce the settling time of a macro-micro positioning stage by employing a designed spring-piezoelectric microstage. The main points of the RDP method are that it can start up the microstage at appropriate moment with proper extension to work against the macromotion vibration. Once the stage vibration amplitude is reduced to the piezoelectric element stroke limit, the micromotion is actuated to approach its final position. In this study, the start-up conditions and extension amount of the piezoelectric element were determined for implementing the RDP method. The feasibility of the method was clarified through theoretical analysis, including dynamic modeling, natural frequency analysis, and a vibration reduction and error compensation analysis. The experimental work was carried out, and the results validated the effectiveness of the RDP method in settling time reduction at different movements. With the assistance of the RDP method, the macro-micro high-speed, large-stroke stage can achieve an effective settling time reduction without sacrificing its accuracy.

Servo systems driven by a permanent magnet linear synchronous motor (PMLSM) are often affected by uncertain disturbances, such as magnetic resistance, friction, and external disturbances, which increase tracking errors and reduce motion accuracy. Traditional control methods may have difficulty to achieve satisfactory control performance in terms of tracking accuracy and disturbance rejection. In this paper, we propose an internal model control PID method based on a model linear extended state observer, which is termed as IMC-PID-MLESO method. With this method, the nominal model parameters of the PMLSM servo system are obtained via system identification. The model linear extended state observer (MLESO), with known parameter information, is designed to improve the estimation accuracy for the system states and total unknown uncertainties. As the uncertainties are compensated in the feedback control law, the PMLSM servo system model is transformed into a known nominal model. Based on the nominal model, the IMC-PID feedback controller is designed to ensure satisfactory performance on disturbance rejection and tracking error reduction. Simulation and experimental results show that the IMC-PID-MLESO method can effectively improve the position tracking accuracy of the PMLSM servo system and rapidly suppress the system disturbance.

Phase-shifting profilometry (PSP) is a method used to establish the pixel correspondence between a projector and a camera using phase-shifting fringe patterns. Due to the nonlinear intensity response of the captured images, nonlinear errors will be induced into the calculated phase and thus decrease the accuracy of 3-D measurement. In this article, we propose a fast self-correction algorithm to reduce the nonlinear phase error without the need for additional projections or precalibration. In this study, we derived an average intensity expression of the captured fringe images that contain the nonlinear response parameters. We can establish a set of equations with the known projection fringe information and unknown nonlinear parameters based on the captured fringe images at different frequencies used in the multifrequency heterodyne algorithm. Based on the equation set, the nonlinear response parameters can be solved for each pixel in the captured images, and the inverse function of the system response can thus be obtained and used to correct the actual nonlinear gray value. This pointwise correction algorithm can reduce the nonlinear phase error corresponding to different frequency fringe images without increasing the number of projections and with no excessive calculation time. Furthermore, this method can use small-pitch fringe patterns to improve the measurement accuracy while maintaining the reliability of the phase unwrapping. Experimental results show that the proposed method can eliminate the nonlinear phase error, improve phase unwrapping robustness, and achieve a high measurement quality for fast 3-D measurement through PSP.

Flip-chip bonding system has a high demand for both force sensing and control functions to guarantee the high-quality chip interconnection. The motivation of this work is to combine the ability to enable a flip-chip bonding system to run in the manner of active soft-landing interconnection. The developed flexure bonder achieves these properties by designing a flexure force sensing and control mechanism integrated with strain gauge sensing and piezoelectric actuating functions. Firstly, the design, modeling and optimization of the flexure mechanism are presented. Theoretical analyses including force sensing and control working principle demonstration, force-strain model derivation and dynamics response modeling are carried out, respectively. Besides, aiming at highly sensitive force control under high-dynamic working condition, the mechanism is optimized by the multi-objective genetic optimization algorithm. Then, this flexure bonder mechanism is analyzed and evaluated by Finite Element Analysis. Finally, a series of validation experiments including force sensing calibration and performance tests, open- and closed-loop force controlling tests, active soft-landing tests and actual bonding tests are successfully implemented. The experimental results indicate that the operation accuracy of the developed system is improved up to $\pm$ 1 N under 400 N range, the overshoot of active soft-landing is less than 2 N under 6000 N/s loading speed. All the results uniformly confirm that the proposed bonding system can achieve precise force control and satisfactory chip interconnection performance with the proposed active soft-landing bonding strategy.